Wissenschaftliches Programm: Donnerstag, 23. November

Introduction

Spasticity occurs with upper motor neuron lesion in cerebral palsy, acquired brain injury or spinal cord injury. Thus, spasticity affects a heterogenous group of individuals, ranging from slight dysfunction to severe disability. Spasticity-reducing surgery has been shown promising results in short term follow up regarding function and patient satisfaction. Nevertheless, only little is known about long term outcome especially concerning reoperation in recurring spasticity.

Methods

This is a retrospective consecutive case series of reoperations in spasticity-reducing surgery in the upper extremity in our center since 2014. We define reoperation as repeat surgery because of reappearance of spasticity at the same level (shoulder, elbow, forearm, wrist, finger, thumb). Demographic data, causative pathology for spasticity and time period between prior surgery and reoperation are analyzed. Patients are allocated to a non-, low- and high-functional status as proposed by Ramström (2021).

Results

From 2014 until 2023 we performed 118 spasticity-reducing surgeries in the upper extremity.  We found 20 reoperations, 15 of which were multi-level surgeries.  Recurrence of finger flexion spasticity appeared most often (11 cases), 7 of them needed a correction of intrinsic tightness. Further we recorded recurrence of wrist flexion deformity in 9 cases, thumb spasticity in 7 cases and forearm rotation spasticity in 3 cases. Regardless their pathology, we classified 5 patients as high-, 9 patients as low- and 6 patients as non-functional. Surgical procedures in reoperations included tendon re-lengthening and release, tendon transfer, hyperselective/selective neurectomy and arthrodesis.

Conclusion

Spasticity is a dynamic, time-evolving process. Patients should therefore be informed that spasticity may develop again after successful surgery in the long run. This has particularly been shown for finger flexion spasticity where we emphasize the importance of recognizing intrinsic tightness before and during surgery by clinical testing.

Introduction

Upper limb spasticity-induced deformities inhibit activities of daily living, resulting in impaired self-care and reducing quality of life. The hyper-flexed and ulnar-deviated wrist is a key element of the dysfunction, compromising grip function and causing pain. In patients with longstanding wrist flexion deformity, a palmar subluxation of the Extensor carpi ulnaris (ECU) tendon can be observed. The ECU tendon has a very small wrist extension moment arm but a relatively large ulnar deviation moment arm. Therefore, even a limited palmar subluxation transforms the ECU into a wrist flexor aggravating the flexion-ulnar deviation deformity. Based on this observation, we implemented the transfer of the ECU to Extensor carpi radialis brevis (ECRB) tendon.

Methods and Results

From 2018 to 2022, we performed ECU to ECRB transfer in 47 hands with a mean age of 29 years (range 13 to 64). The preoperative assessments included measurement of wrist flexion deformity and ulnar deviation, Ashworth scale, classification of hand function and survey of the Arm Activity Measure (ARMA) score. These assessments were repeated 6, 12 and 24 (18/40 patients) months postoperative. 42 patients underwent concomitant procedures as tendon lengthening, muscle release or hyperselective neurectomy to correct the entire deformity. In 9 patients with ECU to ECRB transfer, an additional proximal row carpectomy was needed to correct wrist position. The mean wrist flexion deformity preoperative was 90° (range 20° to 130°). At 12 months follow up, a mean resting position of the wrist of 0° was achieved (range 20° of flexion to 30° of extension) and ulnar deviation was corrected (<30°). The improved hand posture remained at 24 months postop control. The assessment of the ARMA score section A showed a decrease from 15 preoperative (maximum disability 32) to 4 at 12 months postop control.

Conclusions

ECU to ECRB transfer rebalances the wrist while maintaining mobility. This procedure is beneficial and feasible in the majority of wrist flexion deformities, including also severe cases with 120° of flexion. Our case series show that by combination of tendon lengthening of spastic wrist and finger flexors with the ECU to ECRB transfer, a more favourable wrist position can be achieved and maintained. The improved wrist position facilitates personal care in the non-functional hands and allows for better grasp - release control in functional hands.

Introduction: Stroke is nowadays a leading cause of disability with devastating sequelae. Nevertheless, not all the muscles are equally affected, as some may turn spastic or paretic and other remain intact. This unique pathophysiological mosaic dictates a precise therapeutic plan. A life-lasting treatment, precisely adapted to every single patient's needs and to disease pattern, is currently missing. Hyperselective muscle denervation and subsequent cognitive reinnervation with appropriate donor nerves may break the pathological spastic circuit and provide volitional muscle control. We performed cognitive nerve transfers in stroke patients and prospectively investigated their effects on clinical and functional level.

Methods: To provide volitional muscle control of finger flexors and wrist/fingers extensors we transferred the nerve branch to brachialis muscle to the anterior interosseous nerve and the nerve branch to the lateral head of triceps to the deep radial nerve in a total of eleven hemiplegic patients. We additionally reinnervated the spastic pronator teres muscle with a branch to the pectoralis major muscle using a vascularised graft. Supplementary surgical steps were performed as needed. Nerve donors had always been carefully selected with a minimum of M4 strength. Clinical and functional outcomes are evaluated 6, 12 months and 24 months after surgery.

Results: So far eleven patients have been operated, seven patients have completed the 12-month and four the 24-month follow-up. All patients presented with an improvement in all clinical and functional scores with statistical significance (p<0.05) for DASH and modified Ashworth scale.

Conclusion: Cognitive muscle reinnervation through selective nerve transfers seems to reduce spasticity while providing volitional control and may offer the possibility for permanent biological improvement of hand function. in stroke patients. A longer follow-up and higher number of patients is needed.

Background
Due to its partially superficial course, the superficial branch of the radial nerve is vulnerable to injury by trauma or surgery potentially leading to neuropathic pain. Different surgical techniques to treat neuroma have been described but so far no one has proven to be superior to the others. The aim of this study was therefore to identify factors influencing the outcome of revision surgery for neuropathic pain of the superficial branch of the radial nerve in our department.
Methods
We reached out to all patients who had undergone revision surgery for neuroma of the superficial branch of the radial nerve between 2010 to 2020 18 patients could be recruited for a follow-up visit. A medical chart review was performed to collect patient, pain-, and treatment-specific factors. Current DASH score, MHQ score, and Pain Detect score as well as a clinical examination were performed. Outcomes were registered.
Results
Post-revision surgery, only 2 (11%) patients were pain-free. Pain did however improve in 16 (88.9%) of patients. Different types of surgery were performed but no superiority of a single technique could be demonstrated. Only 7 (38.9%) of patients returned to their previous field of work. Patients with a postop VAS score >2 were more likely to be smokers and those patients with lesions of the main nerve trunk (as compared to end branch lesions) were more likely to have a persisting VAS score >2.
Conclusion
Patients with injury to the superficial branch of the radial nerve should be informed that while they might not be fully pain-free after revision surgery pain will most likely improve but there is a high risk they might not be able to return to their previous field of work. Additionally, Patients with injury to the superficial branch of the radial nerve should be coached toward smoking cessation.

Objective

To present the surgical technique and preliminary results of treatment of painful digital end-neuromas with targeted muscle reinnervation into lumbrical muscles

Methods

Case presentation-Surgical technique: We performed neuroma excision and targeted muscle reinnervation into the second lumbrical muscle. The motor entry point is found approximately 18mm proximal to the A1 pulley (proximal end) of the middle finger. First, we began by dissecting the nerve to the lumbrical muscle, so that we would not exceed the 20-min tourniquet time for nerve stimulation. The ulnopalmar digital nerve of the index was dissected to the level of the dorsal nerve branch at the metacarpophalangeal joint. Intraneural neurolysis was then performed from distal to proximal over another centimeter to preserve the dorsal branch and reach the target. The recipient nerve was transected about 8mm proximal to the motor entry point. Tension-free coaptation without size discrepancy was possible. The coaptation site was sealed with fibrin glue, and the nerve was blocked with an intraneural injection of ropivacaïn 1%.

Results

At three-month follow-up the patient perceives no pain or slight pain (VAS 1-2) with light touch on the ulnar stump side. So far, we have treated three patients with painful digital stump neuromas with targeted muscle reinnervation into lumbrical muscles. Patient-reported outcomes show significant improvement in quality of life, sleep and mental health.

Conclusion

Targeted muscle reinnervation into expendable hand muscles appears to be a new therapeutic option with promising results. The anatomy is constant, as shown by several previous anatomical studies.

Neuropathic pain after peripheral nerve injury is a debilitating and socio-economically relevant complication. Peripheral nerve surgeons have developed different treatment strategies without one being accepted as gold standard.

We report a case of a 32-years-old patient with severe neuropathic pain due to a lesion of the median nerve of the right dominant hand following a milling injury 5 years ago. The injury was treated with N1-3 reconstruction using Avance® allografts. Within one year the patient developed severe allodynia in the palm with a Tinel sign. Nerve conduction studies and ultrasound revealed intact nerves to all digits with neuroma formation. Three years after the initial reconstruction, revision surgery with N1-N3 neuroma excision and autologous medial antebrachial cutaneous nerve grafting of N1/N2 as well as end-to-side neurorrhaphy of N3 to N4 was performed. Despite revision surgery and ongoing intense occupational therapy as well as multimodal pain medication, the patient was unable to move and tolerate touch. 

Two years after the revision surgery, we offered the patient a “last resort” procedure with relocation nerve grafting. For that purpose, the median nerve was re-decompressed and the affected digital nerves were intraneurally dissected out of the palm using microscopical magnification with preservation of the motor branch to the thenar. Using a 70mm Avance® allograft, the nerves were buried in the forearm between the superficial and deep flexor muscle bellies. Special attention was given to prevent a mechanical conflict of the buried allograft and the gliding flexor tendons. Perioperative pain treatment was achieved with a supraclavicular pain catheter over 5 days.

Six weeks postoperatively the patient reported significant pain relief with VAS reduction from 10 to 2 during movement and 3 to 0 at rest as well as thumb opposition from full immobility due to pain to Kapandji 7. After almost 5 years of debilitating pain he is now using the hand again with a grip strength of 8kg (preoperatively, 0 kg). The ongoing follow-up is pending.

In conclusion, neurotomy with nerve stump relocation into muscle, vein or bone is described in the literature with inconsistent long-term results. Relocation nerve grafting using long allografts is a promising and powerful tool that might become a gamechanger in the treatment of invalidating neuropathic pain.

Background: Commonly used high-strength suture material for tendon transfer surgeries is designed to withstand high tensile forces and secure the repaired structures in place. However, slippage of the knot is inevitable when these sutures are heavily loaded leading to laxity and gap formation between the repaired structures. On the other hand, early mobilization after tendon transfer surgery is crucial to avoid commonly observed postoperative soft tissue adhesions. Recently, a new suture was introduced (Dynacord) with a salt-infused silicone core which is designed to minimize laxity and preserve consistent tissue approximation. Aims: To compare the biomechanical competence of Dynacord against a conventional high strength suture (Fiberwire) in a human cadaveric tendon transfer model under an early rehabilitation protocol. Methods: Tendon transfers (FDS IV to FPL) were performed in 8 pairs human cadaveric forearms using either Dynacord (DC) or Fiberwire (FW) in a paired study design. Markings were made approximately 1cm proximal and 1cm distal to the level of the interweaving zone of the transfer. All specimens underwent repetitive thumb flexion against resistance in nine intermittent series of 300 cycles each, simulating the postoperative rehabilitation protocol. After each series the distance of the proximal marker to the interweaving zone (proximal), the length of the interweaving zone (intermediate) and the distance of the distal marker to the interweaving zone (distal) were measured. Results: Pooled data over all nine series, normalized to the immediate postoperative status, demonstrated significantly higher zone lengthening for FW compared to DC (p≤0.038) proximally and distally. However, at the intermediate zone, DC was associated with significant (p<0.001) length shortening compared to FW, the latter remaining without length changes. Proximally, whereas for FW zone lengthening significantly increased over the cycles (p=0.009) it remained neutral for DC (p=0.132). Distally, both sutures remained without significant length changes over the cycles (p≥0.105). Conclusion: Biomechanically, DC preserved or even increased tissue approximation, and can thus be considered as valid alternative suture material to a conventional high-strength suture, the latter leading to a significant tissue laxity under cyclic loading. Therefore, DC might allow for a more aggressive early postoperative rehabilitation program to avoid soft tissue adhesion and thus reoperations.

Introduction

Unstable ECU tendinopathy results from dysfunction of the 6th extensor tendon compartment and leads to subluxation/dislocation of the ECU tendon. If symptomatic, surgical ECU tendon stabilization may be performed. Various surgical techniques have been described. The assessment of postoperative stability by MRI however, is only mentioned in one publication demonstrating persistent subluxation in almost 50% of the patients despite good clinical results.

Method

From 2014 -2022, 34 patients were operated using our technique. The ECU tendon is stabilized with a radially based extensor retinaculum flap. The ECU tendon undersurface and subsheath are debrided - if necessary. The lower surface of the retinaculum strip is anchored to either the subsheath or the forearm fascia on the ulnar side. On the radial side, the flap is fixed to itself with a sling around the ECU tendon. This provides radial and ulnar stability and still allows the ECU tendon to glide. Postoperative standardized ultrasound images were performed in 27 individuals, in 19 cases compared to the opposite side. The localization of the ECU tendon in relation to the ulnastyloid during supination was measured. Clinical function was assessed by measuring range of motion, grip strength and PROMs (Quick DASH, PRWE). The mean follow-up was 21 (4-100) months.

Results

In 2 of 34 of the operated patients an ulnar dislocation of the ECU tendon was confirmed. The others showed a variable ECU translation within the osseous groove, as described in healthy/asymptomatic subjects. Of these, 4 showed no translation, 5 showed translation to below the apex and 8 showed translation to the level of the apex of the osseous groove of the distal ulna. Clinical outcome varied depending on concomitant pathologies, treated during the same operation. There was no persistence of painful snapping in any of the patients after surgery. No revisions were necessary.

Discussion

Our technique provides sufficient stability to prevent painful snapping after ECU tendon stabilization. An asymptomatic ECU translation is present in most operated cases, to a similar extent as on the healthy opposite side. The clinical results are good to very good, depending on concomitant pathologies. Despite 2 complete dislocations, no revision surgery had to be performed. We present a low-complication rate in a reliable technique for the treatment of painful ECU tendon instability.

Introduction:

Recent epidemiological studies have revealed an increase in distal radius volar locking plate fixation over the last 20 years, with no corresponding increase in hardware removal. Serious hardware complications, such as tendon irritation or rupture, remain a major concern, with rates of up to 4% reported. Despite recognition of risk factors [such as reduced volar tilt or Soong grade 2] clear clinical guidelines to aid the surgeon on necessity and timing of plate removal are yet to be established. Thus, the primary objective of this study is to investigate if ultrasound can identify tendinopathy secondary to distal radius volar locking plates.

Methods:

All patients who received a removal of volar distal radius locking plate between March 2022 and January 2023 were included in this study. Preoperative clinical assessment included an examination for flexor tendon crepitus, pain during thumb or finger flexion, swelling of the forearm and carpal tunnel syndrome. Soong’s grade was determined on x-ray prior to the removal. The presence of tenosynovitis, tendon fibre continuity, soft tissue cover of the plate and pronator quadratus function were preoperatively assessed with ultrasound and intraoperatively verified. The intraoperative measurements were compared to the preoperative findings, to determine any relationship between the two and whether the use of ultrasound if useful in identifying patients at risk of tendon pathology from volar wrist plates.

Results:

We had a total of 46 patients (out of 47 recruited) who were assessed in the 3-step process. Mean age was 50 years (19-90 years). 7 patients had a Soong grad 0, 26 a grade 1 and 12 patients a grade 2. Intraoperatively, 28 patients showed a tenosynovitis and 8 a tendon fiber discontinuity. The preoperative clinical findings did not correlate with intraoperative tenosynovitis or tendon injury, and the relationship between intraoperative tendon fibre continuity and ultrasound flexor tendon morphology was not statistically significant (p=0.68). The relationship of soft tissue (plate cover and pronator quadratus function) sonographic measurements and intraoperative findings were significant (OR 5.82 (1.23-26.25) and 15.17 (1.67-137.44), and p<0.022 and p<0.016).

Conclusion:

The ultrasound is able to assess soft tissue and pronator quadratus thickness but is not able to reliably predict tendon pathology. Clinical assessments of tendon irritation do not correlate with intraoperative findings.

Introduction

The dart-throwing motion (DTM) is a wrist motion along an oblique plane from radial extension to ulnar flexion. We recorded 2020 the DTM in healthy volunteers and patients following radioscapholunate (RSL) fusion and midcarpal (MC) fusion with three-dimensional motion capture system in vivo, using digital infrared cameras to track the movement of reflective skin markers on the hand and forearm. The aim of this study was to confirm the DTM to be the major movement plane during four activities of daily living (ADL): hammering and opening a jar, a bottle and a yoghurt.

Method

Twenty healthy volunteers and patients who had been treated by RSL (n=7) or MC fusion (n=9) were recorded with a 3D motion capture system during the performance of four ADL's: hammering, opening a jar, bottle and yoghurt. The wrist joint angles were calculated and the plane of the DTM was defined by fitting a linear trend line of best fit to the plotted data of the flexion-extension angle against the radial-ulnar deviation angle for each DTM and ADL trial. The angle of this regression line to the flexion axis was then calculated using standard trigonometric functions.

Results

Overall, wrist motion has been approximated to the DTM (24°) when hammering (35°) and opening a yoghurt (28°), but not during opening a bottle (-35°) or a jar (-31°). There was no significant difference of the calculated angle of the linear trend line between patients after RSL and MC fusion (p>0.25) or between healthy subjects and RSL (p>0.08) or MC (p>0.25) patients' group. Furthermore, motion patterns were inconsistent among the group in the jar and yoghurt opening tasks. Despite DTM was confirmed for opening a yoghurt, two healthy and one RSL patient did move in a plane oblique to the DTM plane. For opening a jar, wrist motion has been approximated to the DTM in seven healthy subjects and one RSL patient, while the other participants moved from ulnar-flexion to radial-extension. During opening a bottle, most participants executed a circular movement in the wrist that could not be represented by fitting a linear trend line.

Conclusion

The DTM was confirmed in 50% of the examined ADL's in the healthy group and patients after RSL and MC fusion. The range of motion of the patients after RSL fusion was in ADL's with and without confirmed DTM significantly reduced compared to the patients after MC fusion. RSL fusion allow not better wrist function during ADL's by preserving the DTM.

Objectives

Three-dimensional (3D) understanding of the combined forearm anatomy is crucial to improve anatomic fixation of forearm fractures, enhance accuracy in correction osteotomy or refine osteosynthesis and prosthetic implants especially the ulnar head prothesis. Most analyses use the two-dimensional surface of the bones, but not a reduce-to-point or reduce-to-line method. Likewise, no study investigated the three-dimensional correlation of the radial and the ulnar bowing.

Methods

CT scans of forearms of thirty healthy and asymptomatic patients were analyzed by using a three-dimensional surface calculation program. Each 3D bone model was divided along the functional forearm rotation axis into 10 equal parts to obtain 11 radial and ulnar cross-sections with a central point each. The connection of these central points led to the central line which then was analyzed in regard of bowing in the 3D space. This central-line-method allowed to find deformity planes out of the usually discussed coronal and sagittal planes as well as to analysis deviations of the anatomical axis eg. at the distal end of the ulna.

Results

The mean axis deviation of the radius is 6.45 mm at 52% of the total length (from proximal to distal) in the coronal plane, 1.35 mm at 38% in the sagittal plane and 7.28mm at 41% in the main deformity plane. The mean axis deviation of the ulna is 8.26 mm at 27% of the total length (from proximal to distal) in the coronal plane, 9.49 mm at 26% in the sagittal plane and 12.68 mm at 7.7% in the main deformity plane. The main deformity plane for the radius and ulna is oriented radio-dorsal with a dorsal tilt of 15° for the radius and 63° for the ulna. An average deviation of the medullary canal of 0.5° towards ulnar and 11° towards dorsal was found at 22 mm and 0.3° ulnar and 8° dorsal at 44mm from the distal ulna respectively. No strong correlation could be found between radial and ulnar bowing in the ulno-radial plane (R2 < 0.01), dorso-palmar plane (R2 = 0.04) or along the main deformity axis (R2 = 0.16).

Conclusion 

The central line method enables to describe bowing of the forearm and to find deformity planes out of the standard coronal and sagittal plane.

This study provides clinically relevant anthropometric data for corrective osteotomy and implantation of ulnar head prosthesis. In case of isolated increased bowing of the radius or ulna, no strong positive or negative correlation can be expected on the other bone.

Purpose:

Arthroplasty of the distal radioulnar joint (DRUJ) using a semiconstrained implant yields good outcomes according to the literature. The aim of this study is to investigate outcomes in 34 patients operated in our institution between 2010 and 2021 and compare them with our previously published follow-up results in 2019 and 2016.

Methods:

36 patients were operated in our institution between 2010 and 2021 for a symptomatic condition of the DRUJ with a semiconstrained implant (Scheker). Two patients were lost to follow-up. 34 Patients completed patient-rated wrist/hand evaluation (PRWHE) questionnaires. The primary endpoint of this study is to assess weight-bearing ability and active range of motion of the DRUJ after implantation of a Scheker total distal radioulnar joint prosthesis. Secondary objectives are to explore the X-rays especially for stability and explore the relationship between clinical and patient-reported outcomes postoperatively. Details about concomitant procedures and subsequent revision surgery is collected.

Results:

We report our results of 34 patients operated in our institution with a semiconstrained distal radioulnar joint prosthesis (Scheker) between 2010 and 2021. Results are compared with our previously published follow-up investigations in 2019 and 2016. Mean follow-up was 5.3 years. The average age of examinated patients was 51 years. The arthroplasty indication was osteoarthritis and/or instability of the DRUJ. Overall pain reduction was significant and active range of motion as well as weight-bearing ability was stable over time. We observed no infection or wound healing problems. Our investigation in 2019 showed a relatively high complication rate with nerve irritation problems (2), heterotopic ossifications and implant loosing (2), ulnar impaction syndrome (1) and allergic reaction to the metal alloy (1) requiring revision surgery. This current study shows lower complication rates in patients operated after our last investigation.

Conclusion:

Arthroplasty with the semiconstrained DRUJ implant reduces pain and improves function. The complication rate was high in the first nine patients treated at our facility. We observed a learning curve with lower complication rate in our recent investigation. An extremely precise surgical technique is mandatory to avoid complications.

Background: Diagnosis of scaphoid non-unions is often delayed, usually because of missing fracture signs on x-rays as first line diagnostics. Whether the healing rate is less or similar in delayed surgery, compared to early surgery is unclear.

Methods: A retrospective data analysis was performed of scaphoid reconstructions in patients with non-unions between 2002 and 2020. General demographics, data of treatment and follow ups were collected. Consolidation was assessed in computer tomography and in a few cases in x-rays. Patients were distributed into 5 groups. In group 1 with the time from accident to indication for surgery below 3m (m=months) were 24 patients, group 2: 21 patients (3-6m), group 3: 31 patients (6-12m), group 4: 23 patients (12-24m), group 5: 23 patients (>24m).

Results: 122 patients (110 male, 12 female) were included, mean age at surgery 28y (y = years, standard deviation 12). 65 were smokers, 26 non-smokers and 31 unknown. The utilizied bone grafts were radius spongiosa in 16 cases, iliac crest in 50, vascularized graft in 55, none in 1. The reconstructions healed in 109 patients and did not in 13. Median days from accident to indication for surgery were 422 days for non-consolidated reconstructions und 241 for consolidated (p=0.05). There was a statistically significant association between time to consolidation and time to surgery (p<0.001). Difference in sex, smoker status and bone graft between consolidated and non-consolidated patients was not significant (p=0.36-1). Of all healed reconstructions, in group 1 100% (n=22) healed within 6m and in groups 2-5 86-100% (n=17-24) within 1y. The time for consolidation was independent from sex, smoker status (p=0.22-0.82), but significantly longer in patients with vascularized bone graft (p=0.03). In group 1-4 a pseudarthrosis persisted in 5-10% (n=1-3) and in group 5 in 22% (n=5). Of these, 6 were re-reconstructed and 7 denied another surgery.

Conclusion: Delayed surgery of scaphoid non-union 3m to even >2y after the accident seems to yield a good potential for healing. However, when surgery is performed more than 2y after the accident the risk for a permanent pseudarthrosis is higher.

Introduction:

Carpal kinematics depends on the complex carpal architecture with multiple joints and intrinsic and extrinsic ligaments interacting with each other. The use of 4D-CT has brought new insights to this topic and allows for a more detailed analysis of the isolated joints. A thorough understanding of wrist kinematics is mandatory when aiming for restoration of wrist function with ligament reconstructions or carpal bone replacements. The aim of this study was to define rotational axes of the carpal joints in healthy volunteers and in cadaver wrists after lunate or scaphoid replacement with intrinsic and extrinsic ligament reconstruction. This leads to a better understanding of the interactions of the carpals in a healthy wrist and whether it is possible to restore rotational axes by replacing the scaphoid or the lunate. This study was supported by Medartis AG and Arthrex.

Material and Methods:

21 subjects with healthy wrists underwent 4D-CT scans of both wrists. 14 cadaver wrists underwent 4D-CT scans before and after scaphoid (n=8) or lunate replacement (n=6) with intrinsic (SLL/LT) and extrinsic (LRL) ligament reconstruction. Rotation axes of the scapho-lunate, scapho-radial, luno-triquetral and luno-radial joints were represented by finite helical axes (FHA). All rotation axes were reported with respect to a coordinate system based on the distal radius and an average FHA was calculated for each joint. The rotation axes of the cadaver wrists before and after carpal bone replacement and with intact and cut LRL-reconstruction were calculated and compared to the healthy subjects.

Results:

Orientation of rotation axes showed substantial inter-individual differences. 68% of rotation axes of native cadavers lied within the range of axes of the healthy wrists. 53% of the cadaver axes after carpal replacement showed deviations <5° compared to the native state. 41% of the axes after lunate replacement showed >5° deviations between intact and cut LRL ligament.

Discussion:

The large range of the orientation of rotation axes in healthy wrists reflects the high inter-individual differences of the bony shape of the carpals and thus, the orientation of the intercarpal joints. Most rotation axes of the native cadaver wrists were found within the range of healthy wrists, which in most cases was even preserved after scaphoid or lunate replacement. This indicates that scaphoid and lunate replacement allows to restore carpal kinematics close to normal in a cadaver model.

Introduction. Currently, there is no consensus on the optimal surgical approach for scaphoid pseudo-arthrosis. Open bone grafting is likely to result in better carpal alignment than arthroscopic bone grafting, but is without known clinical relevance. The aim of this study was to compare clinical and radiological outcomes of arthroscopically and openly treated scaphoid pseudo-arthrosis focusing on function and time to consolidation. 

Methods. This retrospective, comparative, monocentric case-control study included 51 patients with scaphoid pseudo-arthrosis treated either arthroscopically (20) or through an open approach (31). We compared pain, range of motion of the wrist (versus contralateral side) in relation to flexion/extension, radial-/ulnarduction, pro-/supination as well as grip strength (percentage compared to opposite side). Further study parameters include DASH and Mayo Wrist score, time to consolidation, incidence of post-traumatic arthrosis, complications and revision rate. The aforementioned data was analyzed approximately 9 months after surgery.

Results. The mean operating time was 03:02 hours for the open approach versus 02:05 hours in arthroscopically treated pseudo-arthrosis (31% reduction). There was no difference in terms of postoperative pain. The average range of wrist motion, compared to the healthy contralateral side, consisted of flexion (arthr. 90%; open 84%), extension (arthr. 87%; open 89%), pronation (arthr. 100%; open 97%), supination (arthr. 97%; open 97%), radialduction (arthr. 84%; open 87%), ulnarduction (arthr. 80%; open 90%). Especially grip strength in the arthroscopic group (arthr. 85%; open 80%) showed clear superiority. The incidence of post-traumatic osteoarthrosis and the reoperation rate were comparable.

Discussion. The arthroscopic procedure demonstrates a viable alternative to the open method with comparable postoperative subjective outcomes, a similarly satisfactory range of motion and comparable strength measurements. Operating time is significantly shorter in the arthroscopic approach and it can be done in an outpatient setting. Furthermore, the arthroscopic approach is associated with a potentially significant cost reduction. Therefore, this procedure proves an increasingly important alternative. 

Conclusion. This study supports the treatment of scaphoid pseudo-arthrosis using an arthroscopic approach, a more time-efficient and cost effective alternative with comparable functional outcomes to the open approach.

The aim of this study was to assess bone healing and secondary fracture displacement after corrective osteotomy of the distal radius without any cortical contact using palmar locking plates without bone grafting. Between 2009 and 2021, 11 palmar corrective osteotomies of extra-articular malunited distal radius fractures and palmar plate fixations without the use of bone grafts and without cortical contact were assessed. All patients showed complete osseous restoration and significant improvement in all radiographic parameters. Except for one patient, there were no secondary dislocations or loss of reduction in the postoperative follow-up. Bone grafts may not be mandatory for bone healing and prevention of secondary fracture displacement after palmar corrective osteotomy without cortical contact and fixation with palmar locking plate.

Introduction: The implementation of artificial intelligence (AI) in hand surgery and rehabilitation is gaining popularity. Many publications describe powerful AI-enabled algorithms targeting a variety of tasks with often equal or better diagnostic performances than human observers. Yet there’s only very scarce evidence for real,measurable value in terms of patient outcomes, support of healthcare professionals in clinical decision-making or the potential socio-economic impact on the healthcare system. The aim of this experiment was to investigate the potential significance of artificial intelligence in the emergency treatment of wrist trauma patients.

Material/Method: For this experiment 22 physicians (divided in two groups) were confronted with twenty realistic cases of wrist trauma patients referring to the emergency room. 10 of the patients sustained a distal radius fracture and 10 suffered from a wrist contusion. The physicians had to find the correct diagnosis based on anamnestic, clinical and radiographic information and provide a treatment recommendation in a close-to-reality scenario with different options like adding diagnostic measurements or consulting a senior. One group was assisted by an AI-enabled application which detects and localizes distal radius fractures with near-to-perfect precision. The primary outcome measurement was the diagnostic precision (sensitivity and specificity). Secondary outcome measurements were required time, correctness of the treatment recommendation, number of CT scans and senior consultations, subjective (STAI questionnaire) and objective (HR, BP) stress levels.

Results: We found that the AI-enhanced group detected distal radius fractures with superior sensitivity (p 0.06) and specificity (0.17) than the group without AI support. The differences were not significant. The AI-group used significantly less CT scans to reach the correct diagnosis (p=0.02). Furthermore, the AI-group was on average 9% (180 seconds) faster in answering the cases and significantly less stressed compared to the control group (p-value: 0.05).

Conclusion: Our findings suggest that physicians are more likely to make a correct diagnosis in wrist trauma patients if they are supported by an AI tool with a reduced number of additional diagnostic measurements. Furthermore, the AI tool seems to reduce the stress levels of the physicians during the investigation of the cases which is especially valuable in an increasingly stressful clinical environment.  

Purpose

The purpose of this study is to show accuracy of a Cold Ablation Robot-Guided Laser Osteotome in pre-clinical cadaver tests performing osteotomies in the field of wrist- and forearm surgery.

Methods

Osteotomies were performed with CARLO^® which is a miniaturized ablation laser with an optical system controlled by a navigation system. The energy of a laser pulse hitting the bone tissue heats up the water content of the bone and vaporizes it. The debris is being expelled immediately, providing a clean-cut line with preservation of the bone microstructure. CARLO^® enables new cutting patterns that are impossible to achieve with conventional methods.

A total of 12 corrective laser-osteotomies were performed on the distal metaphyseal radius and ulna. The osteotomies were planned patient specific on a 3D CT-model prior to surgery using CARLO^®’s planning software. On the radii six two plane adjustments were conducted lengthening the radius by 4mm and correcting radial inclination by 10° using a curved sine cut. On the ulnae one plane corrective osteotomies were performed shortening the ulna by 3mm using a sine cut as well. Pre-and postoperative CT-scans were taken to compare the virtual surgical planning with the post-operative results and to show accuracy of the cutting path.

Results

Accuracy measurements of the actual cutting path compared to the planned cut showed a mean deviation of 2.11mm in the osteotomies of the radii and 1.66mm on the ulnae. The inaccuracy could have several possible causes, most probable is that the surface registration was not done careful enough.

However, the resulting corrections showed great precision being at least as accurate as todays techniques using 3D printed patient specific cutting guides and 3D planning methods. After fixation the radii revealed an average lengthening of 4.36mm (planned: 4.00mm), while radial inclination was corrected by 10.55° (planned: 10.00°). The ulnae showed an average correction of 3.05mm (planned: 3.00mm).

Conclusion

First cadaveric results show promising results concerning the accuracy of one and two plane osteotomies in wrist and forearm surgery using a Cold Ablation Robot-Guided Laser Osteotome. Accuracy testing showed that registration of the bone in relation to the patient marker is key to achieve a high precision, therefore it should be done carefully. Future steps are stability testing of the osteosynthesis followed by certification and first use in patients.

Rehabilitation is a central part of the treatment of hand and wrist conditions and it represents the most time-consuming part. Normally, rehabilitation take place partially in the office under the control of the therapist and partially alone at home. This second part is left to the compliance of the patient in term of number of sessions per week and of quality of the exercises. Remote rehabilitation can be a good solution to overcome these problems if a feed-back loop can be established between all the involved stakeholders. ReHub®, a new digital platform for remote rehabilitation that connects the surgeon, the therapist and the patient was developed to fulfil these needs. Based on the clinical information given by the physician, the therapist creates a personalised programme. The platform allows for an automatic tracking of the movements, the data recorded during the exercise are uploaded in the cloud and are used to monitor the improvements. The patient can answer to different questionnaires (PROMs). During the exercise the patient can interact with the platform to learn and monitor the right way to perform the exercises.

In 2021-2022. 50 patients were treated with ReHub® for different upper limb pathologies. Patients received a programme of 3 sessions a week for 4 weeks. The number of sessions executed, the Quick-DASH and the pain levels were measured at the beginning and after 2 and 4 weeks.

The diagnosis treated with ReHub® were 15 distal radius fracture, 10 carpal tunnel release and synovitis, 5 wrist sprain. The compliance rate was 66% and the drop-out rate was 6%. 34 patients filled the QuickDASH and its score improved in all cases of at least 15 points. Pain decreased steadily with an overall reduction of moderate (VAS 4-6) and intense (7-10) from 30.3% at the beginning, to 23.2% at 2 weeks and 6.9% after 4 weeks.

The ReHub® digital platform demonstrated a very high compliance with a very low drop-out rate of only 6%. QuickDASH value improved and pain was reduced significantly. These findings reflect the high satisfaction rate of this new digital tool. Physicians can follow-up the improvements, not only with the automatic movement recognition tool, but also through the PROMs filled out by the patients. The therapists can evaluate the compliance in term of time spent exercising and the quality of the movements. The system proved effective in the rehabilitation of common upper extremity conditions, with a high compliance and patients' satisfaction.

Objective: The fixation of distal radius osteotomy traditionally involves the use of titanium plates and screws, which has certain drawbacks such as soft tissue irritation, the need for removal in many cases, stress shielding, and potential patient intolerance or allergic reactions. In this study, we propose a new surgical technique utilizing 3D printed patient-specific implants made of bioresorbable material. We conducted an in vitro study to evaluate the biomechanical stability, biodegradability, and viability of these implants compared to standard titanium plates.

Methods: We performed an opening wedge osteotomy of the distal radius on five cadavers. The osteotomy was planned virtually using CT scans of the radii and executed with the assistance of 3D printed cutting guides. Cadaver-specific 3D printed wedges made of poly(L-lactide-co-D, L-lactide) with 30% β-tricalcium phosphate (PLDLLA/β-TCP) were inserted into the osteotomy gap. They were designed with a hole for fixation using Arthrex Bio-compression screws (3-3.7 mm). 3D printing was performed using the Arburg Plastic Freeformer. Biomechanical tests were conducted to assess the strength of the fixation technique using the printed implants, comparing them to titanium plate implants. Mechanical tests involving tensile, compression, and bending forces were conducted on the printed implants to evaluate their mechanical performance. Biodegradation studies were carried out by submerging the implants in phosphate buffer solution (PBS) for up to 4 weeks.

Results: Biomechanical investigations indicated that the fixation method utilizing the 3D printed implants could withstand an average axial force of 1879.7 N, which is lower than the titanium plate (2415.55 N) but a load higher than typically encountered during falls.  They thus have the potential to provide sufficient stability as an alternative to standard titanium plates. However, physico-chemical tests revealed material alterations caused by the 3D printing process.

Conclusion: Preliminary results of this study demonstrate promising biomechanical stability and viability of 3D printed bioresorbable implants for distal radius osteotomy. Since the 3D-printing process induced material alterations, further research is required to comprehensively evaluate the long-term viability and safety of this technique. If proven successful, these patient-specific implants could offer a beneficial alternative to traditional titanium plates.

Introduction

Multiple techniques are available for reconstruction of digital nerve defects using autograft, allograft and conduits. So far, comparative studies demonstrate variable results ranging from no difference in sensory outcomes to superior recovery with allograft and autograft reconstruction. SILKBridge^®, a novel hybrid three-layered tube based on silk fibroin (obtained from the silk of Bombyx mori) was developed with optimized characteristics for peripheral nerve regeneration. The device has two electrospun layers (inner and outer) and an intermediate textile one. The first in-human pilot study of digital nerve reconstruction with SILKBridge^® was performed in our institution and has proven its feasibility, safety and efficiency in the mid-term follow-up. We examined the long-term results in terms of function, patient satisfaction and biological behavior of the silk fibroin device.

Patients and methods

This is a follow-up study including patients with digital finger reconstruction with SILKBridge^® following traumatic injury or neuroma resection. We collected data from last follow-up during routine clinical controls. Two-point discrimination, Tinel sign, local soft tissue conditions and pain were assessed. Ultrasound examination was performed for long term evaluation of conduit integration properties.

Results

In total four patients were included with median follow-up time of 3 years (1-3.5). All patients showed a good sensation recovery with a static 2-point discrimination of 5-12mm, a moving 2-PD of 4-10mm. No local signs of chronic inflammation or foreign body reaction were observed and a Tinel sign was absent in all patients. The scar was soft and the digital range of motion was the same on both sides. All patients were pain free and satisfied with the result, while no one reported a foreign body sensation. The silk conduit was still visible in the ultrasound but without signs of scar tethering or soft tissue reaction.

Discussion

This is the first long-term follow-up after digital nerve reconstruction with the hybrid, multi-layered silk fibroin device SILKBridge^®. So far, functional results and patient satisfaction are excellent with no adverse events. SILKBridge^® appears to be a safe and efficient alternative to nerve autografts or allografts in cases of digital nerve defects with very good long-term biological behavior.

Objectives:

With percutaneous pulley release becoming more popular, safety and reliability of this mini-invasive procedure remain a concern. Visualization of the surgical steps by ultrasound suggests increased safety but also highlights the proximity of tendons, nerves and vessels as well as the potential for damage to these structures. Therefore, proper instrumentation is crucial. We present the results of implementing sonographically guided mini-invasive A1 pulley release using a newly designed guide instrument and a commercial hook knife.

Methods:

Initially, basics for the technique using an early version of the guide instrument were established in cadaver hands. The instrument design was subsequently refined. Between November 2019 and December 2022 a total of 128 sonographically guided A1 pulley release procedures were performed in 79 patients.

The guide instrument is inserted through a small incision at the base of the finger and enters the flexor tendon sheath between the A1 and A2 pulley. It is advanced proximally between the flexor tendon and the A1 pulley under sonographic visualization. Once in position, the hook knife is inserted through the channel in the guide instrument. The central position over the pulley is sonographically confirmed, before turning the hook knife 90°. Finally, the pulley is released by retracting the hook knife distally.

Results and Conclusions:

Complications include one case of inadvertent skin laceration, one case of postoperative infection and one CRPS. Postoperative recurrence of a trigger finger due to incomplete pulley release was noted in 3 cases, in one of which the issue was resolved sonographically. The second had a remission after cortisone infiltration while the last underwent open pulley release revealing an intact A1 pulley. Intraoperative conversion to open release was performed in 5 cases due to an unfavorable position of the hook knife or persistent trigger finger intraoperatively. Of the 79 operated patients 68 (106 of 128 A1 pulley releases) reported return to strenuous activities within two weeks. No injuries to nerves, vessels or tendons occurred.

In conclusion, the choice of appropriate surgical instruments and practice allows for safe and efficient implementation of a mini-invasive procedure in pulley release.

Introduction: Treatment of skin defects on the hand with exposed tendons, nerves or bones after severe trauma/infections can be a reconstructive challenge. Biodegradable Temporising Matrix (BTM®) may serve as a new soft tissue cover alternative if skin grafts alone do not heal and flaps are not an option, especially in patients that are not ideal candidates for major complex microsurgical reconstruction. BTM is a synthethic polyurethane dermal substitute. This case series represents the first study evaluating the efficacy of BTM in no-burns reconstruction. Method: In the year 2022, 27 patients were treated with BTM. In 20 cases the soft tissue defect was caused by a severe trauma. In four patients, there was a skin defect after an infection and in one case each, it was caused by an epitheloid sarcoma, by Dupuytren’s disease and by MDA5 Dermatomyositis. 59% of the patients were male, the median age was 51 years. Four patients suffered from an amputation of a finger, 18 patients had a substantial defect at the dorsum of the hand, three patients at the forearm, and one patient each had a defect at the thenar or palm. The size of the skin defect ranged from 1 to 200 cm². Following debridement, BTM was applied to the wound. After the granulation tissue has fully integrated into the BTM layer, the sealing membrane is removed and a new, vascularized dermal layer emerges. A split-thickness skin graft was then applied. Results: On average, the delay between covering the soft tissue defect with BTM and the application of a split-thickness skin graft was 36 days. BTM was applied in 9 cases on exposed extensor tendons, in 4 cases on muscle or soft tissue, in 5 cases on bone, in 2 cases on the neurovascular bundle and in 1 case each on exposed flexor tendon and nerve transfer. One infection with enterobacter cloacae was observed. The split-thickness graft was well integrated after five days. At follow-up the ROM was satisfying according to the accompanying injuries. Conclusion: According to the statistics and experience gained, the use of BTM demonstrates enormous potential in healing complex wounds. It shows reliable healing and the scars after BTM application and split thickness skin grafts were aesthetically very pleasing. Coverage of tendons, nerves and bones are possible as well as coverage of infected wounds. The method should be preferred especially in patients, who do not qualify for a vascularized free or pedicled flap with reduced mobility requirements.

Introduction: Deep Learning and especially Convolutional Neural Networks (CNN) have established themselves as state-of-the-art methods in the field of image and object detection throughout the last decade. In health care they are successfully used, for example, to detect skin or breast cancer, where they reach the level of an expert opinion.

The aim of this study was to build an deep learning algorithm which is able to automatically recognize the region of interest on standard radiographs, automatically identify and localize distal radius fractures.

Material/Method: A database of conventional radiographs taken from 729 patients was manually built and labelled to serve as ground truth. 409 of these patients sustained a distal radius fracture (verified with X-rays, CT scans and clinical information from follow-up-appointments) and 320 were healthy individuals. By using all wrist X-rays from one institution from one calendar year we achieved a close-to-reality, wide variability of fracture configurations and patient demographics. The dataset was divided into a training- and a test-set. Several object detection deep learning models were trained to recognize the region of interest, to detect and localize distal radius fractures (if present). Furthermore, we explored if using one or two projections (dorsopalmar and lateral) and the addition of demographic data (age, gender) to the algorithm would change the models performance. The CNN model was compared to human observers in order to explore the clinical relevance.

Results: Our best model detected distal radius fractures on dorsopalmar radiographs with an accuracy of 98.5% and an AUC of 0.995 improving on the human baseline accuracy by 18.5%. This corresponds to a sensitivity of 0.987 and a specificity of 0.987. The addition of a second projection (lateral) or demographic data didn’t improve the performance, but the model became more confident in its prediction. The region of interest was reliably recognized using automated detection of three landmark points which led to the inclusion of 99% of all fractures.

Conclusion: Our deep learning model showed high accuracy in the detection and localization of distal radius fractures. In our test setup, it exceeded the performance of human observers. These kinds of Convolutional Neural Networks have the potential to improve the efficiency of healthcare workers and substantially change our way of patient care in the near future.

Introduction:
Grip strength measurement with dynamometers (Jamar) have proven reliable and valid. However, the specific geometry of its handles require a grip position that is rarely found during daily activities. With regard to functional outcome assessments, the aim of this study was to establish a cylindrical hand grip strength device (HGS) and investigate the impact of different handle diameters and forearm rotations on power grip force.

Methods:
25 healthy participants were examined with the HGS during maximum effort trials in a test-retest study using handle diameters of 30mm, 60mm or 100mm, as well as neutral, pronated or supinated forearm rotation. Concurrent validity to the clinical standard (Jamar) was established. Maximum force was compared between conditions and minimal detectable differences (MDD) was evaluated.

Results:

Reliability of the HGS (ICC =0.96, range [.90, 99]) for all observed conditions as well as concurrent validity and device correlation (r=0.91 [.71, .99]) were found to be excellent. Between-session MDD were 83.6N, 85.5N and 32.5N for the 30mm, 60mm and 100mm HGS, respectively, which constitutes of 12.1-16.0% of measured force.

Grip forces were found significantly different between handle diameters (p<0.0001) and forearm positions (p<0.0003). Across all positions, the smaller the diameter, the larger the observed gripping force. Interestingly, the grip force with HGS 30mm was larger in supination than in neutral position while using HGS 60mm, the highest grip force was reached in the neutral position, followed by supination.

Conclusion:
The reliability of the new HGS was similar or better compared to the clinical standard.

Measured grip strength significantly depends on the diameter of the handle and forearm rotation. As known from the ulnar impaction syndrome, pathologies can have an increased influence on grip strength in different positions. We therefore point out the necessity to investigate non-neutral positions and different handle diameters in order to understand healthy and pathological power grip force and its implication on daily activities.

The presented HGS with its cylindrical design in relevant diameters for daily activities are mobile, easy to use, and now proved to be reliable and valid to be used in a clinical setting. They allow continuous recording of grip force and advanced analysis of grip force characteristics, such as loading-rate or centre-of-pressure, to get a more in-depth understanding of grip force characteristics in different pathologies.