Ossification of the posterior capitellum: description of a new pathology and its radiological appearance.

BACKGROUND: Boxer elbow and handball goalkeeper elbow are causes of impingement characterized by osteophytes formation at the olecranon and coronoid tip as well as their corresponding fossae. Herein, we present another distinct pathology in these patients: the formation of an exostosis at the posterolateral aspect of the elbow. METHODS: Between April 2016 and May 2020, 12 athletes with boxer elbow and handball goalkeeper elbow (mean age of 22 years) suffering from elbow pain were enrolled in the present study. Plain radiography, magnetic resonance imaging (MRI), and computer tomography (CT) scans were used to evaluate the bone conformation of the posterolateral aspect of the elbow. Assessment and staging of the ossification was performed by two independent fellowship-trained elbow surgeons. RESULTS: Bone marrow edema of the posterior aspect of the elbow at the origin of the anconeus muscle was initially detected in MRI scans. With the progression of the condition, imaging revealed an ossification posterior to the capitellum with bony bridges. In the advanced stage of the disease, the exostoses was unstable as the ossification had no adherence to the posterior capitellum during surgical excision. Plain radiographs are limited in their ability to detect the condition, whereas MRI and CT scans allow to identify a signal enhancement at the posterolateral aspect of the elbow. CONCLUSION: In patients without history of elbow trauma, bony irregularities of the posterior aspect of the capitellum may indicate ossification of the posterolateral aspect of the elbow, most likely caused by repetitive hyperextensions.

[Coronoid reconstruction with autologous iliac crest bone graft in chronic elbow instability through a medial approach]. / Coronoidaufbau mittels Beckenkammspan über einen medialen Zugang zur Therapie von chronischen Coronoiddefekten mit posteromedialer Rotationsinstabilität.

OBJECTIVE: Neutralizing a posteromedial rotatory instability (PMRI) caused by coronoid deficiency by restoration of the humeroulnar joint surface with an autologous iliac crest bone graft. INDICATIONS: Surgery is indicated in patients with chronic deficiency of the anteromedial facet of the coronoid with subsequent PMRI. CONTRAINDICATIONS: Coronoid reconstruction is not recommended in patients with advanced osteoarthritis of the elbow caused by subluxation of the humeroulnar joint. General contraindications like acute infection, pregnancy and lack of operability should also be taken into account. SURGICAL TECHNIQUE: First, a medial approach is established and the base of the coronoid is prepared. Afterwards an autologous iliac crest bone graft is placed onto the defect and secured by screws or a plate. In addition, a reconstruction of the anterior bundle of the medial collateral ligament with an autologous tendon graft is performed. POSTOPERATIVE MANAGEMENT: An elbow orthesis is worn for 6 weeks after surgery to avoid valgus or varus stress. There is no restriction in range of motion. A continuous passive motion elbow chair supports the patient in regaining elbow mobility. RESULTS: Between 2015 and 2017, we treated 10 patients suffering from chronic coronoid defects with coronoid reconstruction. Eight of the patients were available for follow-up 86 weeks after surgery. The mean age was 41.4 years. In all patients, elbow range of motion and patient-related outcome measures were improved after surgery. Plain radiographs illustrated correct centering of the elbow joint. One patient had to undergo elbow arthroplasty and was excluded. Coronoid reconstruction with an autologous iliac crest bone graft restored humeroulnar joint congruency and improved satisfaction in patients suffering from chronic coronoid deficiency.

Reliability, validity and critical appraisal of the cross-cultural adapted German version of the Mayo Elbow Performance Score (MEPS-G).

BACKGROUND: The Mayo Elbow Performance Score (MEPS) is a rating system consisting of four dimensions to evaluate elbow performance. It is a common tool for assessment of elbow impairments worldwide. We determined the validity and reliability of its German version (MEPS-G) after cross-cultural adaptation. METHODS: Six investigators examined 57 patients with elbow pathologies. The MEPS-G was compared to validated elbow scores such as the German versions of DASH, the Oxford Elbow Score, pain level and subjective elbow performance on a VAS. Inter-rater reliability (IRR) and validity of the score and its dimensions were also reviewed. Verification was performed using the intraclass correlation coefficient (ICC), the prevalence and bias with adjusted Kappa (PABAK) and the Spearman correlation. RESULTS: The IRR of the MEPS-G score was moderate (ICC (2.1) = 0.65). The IRR of the four individual dimensions was moderate to high (KPABAK = 0.55 -0.81). Validity for the sum score (r = 0.52-0.65) and the dimensions pain (r = 0.53-0.62), range of motion (r = 0.7) and stability (r = - 0.61) was verified. The function subscale reached insufficient validity (r = 0.15-0.39). CONCLUSION: The MEPS-G is not sufficiently valid, which is consistent with its English version. The patient-based dimensions were a weakness, demonstrating high risk of bias. There is no general recommendation for the utilization of the MEPS-G as outcome measurement for patients with elbow pathologies.

Overlengthening of the radial column in radial head replacement: a review of the literature and presentation of a classification system.

BACKGROUND: Radial head arthroplasty is a common procedure in elbow surgery. It has been shown to be of benefit for the patients, but there also are relevant complications that should be prevented if possible. One significant complication is overlengthening of the radial head prosthesis. In overlengthening, the head of the prosthesis overextends the physiological level of the native radial head and leads to overcompression in the radiohumeral joint. Rapid erosion and arthritic changes may then impede the clinical outcome. The incidence of overlengthening is not precisely known, but estimations range to up to 20% of all implanted prostheses. METHODS: The present review discusses the available body of literature on overlengthening and lines out a classification system that may be used to guide treatment algorithms. The classification is based on the personal experiences of the author during their clinical practice. RESULTS: In low-grade overlengthening (type I) conservative treatment can be an option. In Types II-IV usually revision surgery is needed. Depending on the state of the capitulum and joint stability, it is possible re-implant a prosthesis, or rely on implant removal alone. DISCUSSION: The present review aimed at shedding light into overlengthening as a complication radial head replacement and to help identify and treat it.

[Bony contact in arthritic and healthy elbow joints : Studies in cadaveric specimens]. / Knöcherne Kontaktpunkte im arthrotischen und gesunden Ellenbogengelenk : Studie am humanen Leichenpräparat.

BACKGROUND: Arthroscopic and open debridement arthroplasty for elbow arthrosis produce excellent results. Resection of the tip of the olecranon and coronoid, as well as debridement of the associated fossae, is frequently described as sufficient for restoring range of motion and reducing pain. OBJECTIVES: The purpose of this study was to demonstrate that medial and lateral osteophytes of the olecranon and the coronoid usually mark the first bony contact and may, therefore, restrict range of motion. MATERIAL AND METHODS: 11 fresh-frozen elbows were dissected. The fossae were coated with Optosil P Plus (C-silicone), and maximal flexion and extension was simulated. The distribution of C­silicone impressions was documented. 6/7 donors were male. The mean age at the time of death was 82 . RESULTS: Out of 11 elbows, 4 exhibited arthritic changes. All arthritic elbows showed marginal osteophytes of the olecranon without characteristic dipping of the olecranon into its fossa. In 1/4 cases, additional osteophytes at the side of the coronoid were detected (in comparison to 1/7 in healthy elbows). CONCLUSION: The distribution of osteophytes in elbow arthrosis may be underestimated. Many clinicians describe a resection of the tip of the olecranon and the coronoid and debridement of the related fossa as sufficient. Our study supports the theory that marginal osteophytes, especially of the olecranon, should be resected during debridement arthroplasty, since the distribution of bony contact differs in arthritic and healthy elbows.

[Performance control after arthroscopic arthrolysis with capsulectomy in fresh-frozen elbow joints]. / Erfolgskontrolle nach arthroskopischer Arthrolyse mit Kapsulektomie am Ellenbogengelenk im Fresh-frozen-Präparat.

BACKGROUND AND OBJECTIVE: Posttraumatic or postoperative movement restrictions in elbow joints can often occur (including capsular contracture) and can generate everyday limitations. In persistent elbow stiffness, arthroscopic arthrolysis with removal of the dorsal and ventral capsule portions can be carried out. The purpose of this study was to assess the efficacy of arthroscopic capsulectomy by means of an in vitro anatomical study. METHODS: A standardized elbow arthroscopy with ventral and dorsal capsulectomy was performed and image-documented in five fresh-frozen elbow specimens. Subsequently, open dissection of the elbow joint was performed to analyze the amount of residual capsule by means of photodocumentation of the specimens. RESULTS: Regardless of the surgeon and surgical experience, anterior and posterior remnants of the capsule remained in all specimens. Dorsal capsule strands around the standard arthroscopy portals were noticed particularly more often in the area of the high dorsolateral camera portal. An incomplete capsulectomy was seen on the ulnar side at the level of the posterior medial ligament (PML) in the immediate vicinity of the ulnar nerve. Ventrally, a capsulectomy was performed from the radial side and also the ulnar side until the brachialis muscle and additionally a complete capsulectomy as far as the anterior medial ligament (AML) and radial collateral ligament (RCL) was achieved. The capsule was completely resected in a proximal direction. Distally, irrelevant capsular remnants were found in the region of the annular ligament and distal of the tip of the coronoid process. CONCLUSION: Arthroscopic arthrolysis can be performed with a high degree of radicality. The radicality must be self-critically taken into account in one's own action. The radicality of the portal change may even be higher ventrally than with an isolated column procedure. On the other hand, it must be critically considered that posteriorly, the PML cannot be adequately addressed by means of arthroscopy due to the risk of ulnar nerve injury. Portal changes might help to enable a more complete visualization of the joint capsule and may avoid leaving possibly relevant remnants of the capsule. If a release of the PML is required, this may have to be carried out in combination with an ulnar nerve release in a mini-open technique.

[The proximal radioulnar joint in consideration of the distal radioulnar joint]. / Das proximale Radioulnargelenk unter Berücksichtigung des distalen Radioulnargelenks.

The movement of the forearm follows a complex interplay of three main components: the proximal and distal radioulnar joint and the interosseous membrane. Injuries to one or even all components have a huge impact on the integrity of this system. The Essex-Lopresti lesion presented a high challenge in clinical diagnostics as well as therapy. Reconstructions of the length and stability are essential for a satisfactory postoperative outcome. If a reconstruction of the radial head by osteosynthesis is not possible, a radial head prosthesis should be implanted in the case of longitudinal instability - avoiding overlapping and/or oversizing. The reconstruction of the interosseous membrane should be considered, as well as the assessment of the distal radioulnar joint and/or the triangular fibrocartilage complex. Various reconstruction options are available in this regard.

Reasons for surgical revision after conservatively treated radial head fractures-retrospective study of 70 patients.

BACKGROUND: An inadequate clinical outcome after conservatively treated radial head fractures is not uncommon. We analyzed the subjective limitations, objective complaints, and surgical procedures for radial head fractures initially treated conservatively. PATIENTS AND METHOD: Between 2007 and 2016, 70 patients (42 men, 28 women) who suffered from fracture sequelae after conservatively treated radial head fractures were examined. Demographic (age, 41.8 years, range, 16-75 years) and clinical data (pain, range of motion, instability) were retrospectively evaluated. RESULTS: The average time to surgery after trauma was 50 months (range, 5-360 months). In 38 cases, radial head fractures were initially treated with immobilization for 3.4 weeks (range, 1-8 weeks). Physiotherapeutic treatment was performed in 39 cases. In only half of the cases was retrospective Mason classification possible: 20 type I, 8 type II, 5 type III, and 2 type IV. Of the 70 patients, 53 had posttraumatic elbow stiffness; 34 had isolated lateral and four patients isolated medial ligament instability. There were eight cases with a combination of lateral and medial ligament instability and 27 cases of elbow stiffness combined with instability. An average of 1.2 (range, 1-4) surgical procedures per patient were performed. In all, 64 patients underwent elbow arthroscopy with arthrolysis and additional treatment depending on other injuries. The range of motion improved on average from preoperative flexion/extension of 131-15-0° to postoperative flexion/extension of 135-5-0° (gain in flexion: 4.2° and extension: 10.6°). CONCLUSION: Conservative treatment of radial head fractures does not always yield good results. Reasons for a poor outcome include chronic instability, cartilage damage, stiffness, or a combination thereof. Improved outcomes can be achieved via arthroscopic arthrolysis.

Correction to: Insertion of the Ascension PyroCarbon PIP total joint in 152 human cadaver fingers: analysis of implant positions and malpositions.

In the experimental study the distal component of the Ascension PyroCarbon proximal interphalangeal total joint prosthesis was implanted 180° rotated. Figures 2-5 show the implant malpositions. The methods, results, and conclusion of the study were not affected by this.

[Destruction of the radial head : Endoprosthesis, autologous reconstruction or anconeus arthroplasty?] / Destruktion des Radiuskopfes : Endoprothese, autologer Aufbau oder Anconeusplastik?

BACKGROUND: Radiocapitellar arthritis or defects most often result from trauma. Most of the patients are young and have high functional demands with high load capacities. Therefore, endoprosthetic options should be postponed for as long as possible. If conservative treatment cannot relieve symptoms sufficiently, radial head preservation, resection or replacement options are at the surgeon's disposal. In early stages of radiocapitellar arthritis, radial head preservation options can be taken into account. The chances ofgood results decrease with increasing cartilage damage. TREATMENT OPTIONS: In addition to radial head preservation options this article discusses radial head resection with and without anconeus interposition and radial head as well as radiocapitellar replacement. Clinical data are rare. The advantages and disadvantages of each option must be discussed with the patient and the decision should be made individually on the basis of patient specific factors. The aim must be to postpone endoprosthetic options - especially total elbow arthroplasty - for as long as possible, while assuring a functional range of motion with an acceptable pain level.

[Post-traumatic arthritis in the young patient : Treatment options before the endoprosthesis]. / Die posttraumatische Arthrose des jungen Patienten : Therapieoptionen vor der Endoprothese.

BACKGROUND: In the young patient, treatment of post-traumatic elbow arthritis remains difficult. Total elbow arthroplasty must be delayed for as long as possible. Therapy starts with nonoperative treatment. If this fails, operative options can be discussed. TREATMENT AIM: The aim of surgery is to provide a functional range of motion with acceptable pain without obstructing future treatment options. THERAPY: Patients with pain at terminal extension and/or flexion may benefit from arthroscopic or open debridement. Patients with advanced osteoarthritis and pain throughout the complete range of motion, who are too young for total elbow arthroplasty, are offered interposition arthroplasty or arthrodesis. Arthrodesis of the elbow leads to significant restrictions in daily life due to the complete loss of extension/flexion. Therefore, arthrodesis is only offered as treatment in exceptional circumstances. Interposition arthroplasty is a reasonable option for the young patient without significant bony defects, which may provide a stable, functional flexion arc with an acceptable pain level. Interposition arthroplasty preserves the revision options of re-interposition arthroplasty as well as the withdrawal to total elbow arthroplasty. Partial and total elbow arthroplasty are treatment options of elbow arthritis but are not subjects of this article.

[Radial Head Replacement - Surgical Technique and Own Clinical Results]. / Radiuskopfendoprothetik - Operationstechnik und eigene Ergebnisse.

BACKGROUND: Radial head arthroplasty is an established method to restore the anatomy and biomechanics of the elbow joint - especially for non-reconstructable radial head fractures. AIMS: This video article aims to explain the indications, the surgical procedure and the postoperative rehabilitation protocol for radial head replacement. We also present our own results with this procedure. MATERIAL AND METHODS: Since 2014, we have prospectively evaluated all patients undergoing surgery for radial head replacement (MoPyC, Tornier, France). A 6 month follow-up of 11 patients is now available. Moreover, 3 retrospective cases with rare complications are reported which were not part of our prospective evaluation. RESULTS: 8 of 11 procedures were performed due to acute, non-reconstructable radial head fractures. Secondary radial head replacement as a result of failed osteosynthesis was performed in the remaining 3 cases. 8 patients had clinically relevant concomitant injuries to the elbow joint. The mean Mayo Elbow Performance Score was 88 points (65 to 100 points). The arc of motion averaged 124° (± 18°). At 6 months, the mean extension lag was 8°. There were no complications requiring revision surgery at 6 months. Retrospective evaluation found one patient with extensive osteolysis due to oversizing of the shaft, one with disconnection of the prosthesis and one with a broken prosthesis shaft. CONCLUSIONS: The clinical results with radial head arthroplasty are promising. Accurate implantation is crucial to minimise the risk of complications requiring revision surgery.

Identification of overlengthening after replacement of the radial head with a bipolar prosthesis.

INTRODUCTION: Overlengthening of the radial column leads to insufficient functionality and increased capitellar wear. Methods to detect or prevent overlengthening have been described for monopolar prostheses. The aim of this study was to evaluate whether one such method described by Athwal et al. is also applicable for a bipolar prosthesis. MATERIALS AND METHODS: The radial heads of six fresh frozen upper extremities were resected. A bipolar radial head prosthesis was implanted in each, and the effects of sequential overlengthening on the alignment of the radiocapitellar and ulnohumeral joint line were recorded by fluoroscopic images. Digital image analysis and estimation of overlengthening followed according to the method described by Athwal et al. RESULTS: Statistical analysis of the estimated and actual differences between the native state and bipolar replacement of the radial head with stepwise overlengthening of 1.5, 3, 4.5, and 6 mm showed a specificity of 86 % but consistently underestimated the amount of overlengthening with a sensitivity of only 61 %. DISCUSSION: The method described by Athwal et al. for the identification of overlengthening by a monopolar prosthesis was not found to be reliable for ruling out or quantifying overlengthening of the tested bipolar prosthesis. However, the use of the method to detect (rule in) overlengthening may be acceptable in certain circumstances. A reliable method for postoperative quantification of overlengthening by bipolar prostheses has still to be found.

[Total Elbow Replacement - Implantation of the Latitude Prosthesis (Tornier)]. / Endoprothetik des Ellenbogengelenks - Implantation am Beispiel der Latitude-Prothese (Tornier).

Due to technical progress, the indication for total elbow arthroplasty could be expanded in recent years. As a result, the demand regarding functionality and mobility of the replaced joint has risen as well. Elbow arthroplasty has to be considered as technically demanding. Only with detailed knowledge of this surgical procedure and its possible intraoperative pitfalls can one provide the best possible results. In this instructional video we explain the implantation of the Latitude elbow prosthesis (Tornier) putting emphasis on the correct approach as well as implantation of the prosthesis and subsequent wound closure.

[Repair of the Pronator Quadratus Muscle with a Part of the Brachioradialis Muscle Insertion]. / Ablösung und Refixierung des M. pronator quadratus mit einem Teil des M. brachioradialis Ansatzes.

BACKGROUND: Most surgeons don't repair the pronator quadratus (PQ) muscle in palmar plate fixation of a distal radius fracture because experience has shown that PQ repair yields no functional advantage. However, repair of the PQ may offer finger flexor tendon protection. METHODS: In 9 human cadavers, the PQ was detached with a strong rim of connective tissue consisting of a fibrous portion of the roof of the first extensor compartment (RFEC) and the palmar limb of the brachioradialis muscle (BR) insertion. The gross anatomy and the dimensions of the dissected tissue were measured. After fixation of a palmar plate, the PQ was repaired. Stability was tested with 100 passive maximum pronation and supination repetitions. RESULTS: The average total width of the PQ with the strong rim of connective tissue consisting of the RFEC and the palmar limb of the BR insertion was 28 mm. Suture repair was possible in each specimen, and each palmar plate was completely covered distally. CONCLUSION: This dissection of the PQ with a strong rim of connective tissue consisting of the RFEC and the palmar limb of the BR insertion may offer a way to cover the distal edge of a palmar plate in open reduction and internal fixation of a distal radius fracture that affords finger flexor tendon protection.

[Double-plate osteosynthesis of the proximal ulna]. / Die Doppelplattenosteosynthese der proximalen Ulna.

OBJECTIVE: Stable osteosynthesis during early postoperative functional treatment, particularly in patients with osteoporosis. INDICATIONS: Metaphyseal fractures, small proximal fragments or avulsion fracture of the triceps tendon, osteotomy of the olecranon, and pseudarthrosis of the olecranon or proximal ulna. CONTRAINDICATIONS: Skin infection, severe soft tissue lesions. SURGICAL TECHNIQUE: Dorsal approach to the olecranon. Open reduction and internal fixation by two side-mounted angular locking compression (double) plates. POSTOPERATIVE MANAGEMENT: Early functional treatment. Full load-bearing after 6-12 weeks postoperatively. RESULTS: A total of 14 patients were treated with double-plate osteosynthesis between 2011 and 2012. Clinical data were analysed retrospectively. The average follow-up was 11.7 months (range, 4-21 months). The mean flexion-extension radius was 123° (100°-140°), the pro-supination radius 166° (160°-170°). Using the Mayo Elbow Performance Score, eight patients had excellent and six good results. The mean Quick-DASH score was 15 (0-50).

The course of the posterior interosseous nerve in relation to the proximal radius: is there a reliable landmark?

PURPOSE: The posterior interosseous nerve (PIN) is closely related to the proximal radius, and it is at risk when approaching the proximal forearm from the ventral and lateral side. This anatomic study analyzes the location of the PIN in relation to the proximal radius depending on forearm rotation by means of a novel investigation design. The purpose of this study is to define landmarks to locate the PIN intraoperatively in order to avoid neurological complications. METHODS: We dissected six upper extremities of fresh-frozen cadaveric specimens. The mean donor age at the time of death was 81.2 years. The PIN was dissected and marked on its course along the proximal forearm with a 0.3-mm flexible radiopaque thread. Three-dimensional (3D) X-ray scans were performed, and the location of the nerve was analyzed in neutral rotation, supination, and pronation. RESULTS: In the coronal view, the PIN crosses the radial neck/shaft at a mean of 33.4 (±5.9)mm below the radial head surface (RHS) in pronation and 16.9 (±5.0)mm in supination. It crosses 4.9 (±2.2)mm distal of the most prominent point of the radial tuberosity (RT) in pronation and 9.6 (±5.2)mm proximal in supination. In the sagittal view, the PIN crosses the proximal radius 61.8 (±2.9)mm below the RHS in pronation and 41.1 (±3.6)mm in supination. The nerve crosses 29.2 (±6.2)mm distal of the RT in pronation and 11.0 (±2.8)mm in supination. CONCLUSION: With this novel design, the RT could be defined as a useful landmark for intraoperative orientation. On a ventral approach, the PIN courses 10mm proximal of it in supination and 5mm distal of it in pronation. Laterally, pronation increases the distance of the PIN to the RT to approximately 3cm.

[Locking plate osteosynthesis of the radial head fractures : clinical and radiological results]. / Winkelstabile Plattenosteosynthese des Radiuskopfes : Klinische und radiologische Ergebnisse.

BACKGROUND: Therapy of radial head fractures is still controversially discussed. Especially comminuted fractures are at risk of complications such as radial head necrosis, nonunion and secondary loss of reduction after open reduction and internal fixation. The aim of this study was to evaluate clinical and radiographic results of ORIF (open reduction internal fixation) of radial head fractures using a new radial head-specific locking plate system. PATIENTS AND METHODS: A total of 21 patients (13 men and 8 women) were treated with locking plate osteosynthesis of radial head fractures. Mean age was 50 years (range 29-67 years). According to the Mason classification, 15 were type III and 6 type IV. Mean time between trauma and surgery was 5.6 days (range 0-23 days). These patients were reexamined using the Mayo Elbow Performance Score and x-rays in two planes. RESULTS: In all, 21 patients were reexamined with a mean follow-up of 12.1 months (range 5-23 months). The mean Mayo Elbow Performance Score was 87.1. Excellent results were obtained in 12 patients, good results in 6 patients, and fair results in 3 patients. Mean extension deficit was 12.1°, mean flexion 135.2°, mean pronation 70.9°, and mean supination 63.6°. All fractures healed uneventfully. There was no complete radial head necrosis but one partial. Four cases of heterotopic ossification were detected: Hastings classification I (n = 2), IIb (n = 1), IIIb (n = 1). CONCLUSION: ORIF of radial head fractures using locking plates can lead to good and excellent results. Modern implants may allow for reconstruction of comminuted fractures avoiding arthroplasty in these young patients.

Insertion of the Ascension PyroCarbon PIP total joint in 152 human cadaver fingers: analysis of implant positions and malpositions.

INTRODUCTION: The Ascension PyroCarbon proximal interphalangeal (PIP) total joint is used in osteoarthritis of the PIP finger joint. No systematic study of the positioning of this prosthesis and its relation to proximal and middle phalanx morphology has yet been reported. MATERIALS AND METHODS: Positioning of the proximal and distal components of the Ascension PyroCarbon PIP total joint was radiographically analysed in 152 human cadaver fingers. RESULTS: Ideal implant position in the axis of the phalanx and with contact of the implant head with bone in both the frontal and sagittal planes was seen in only 33 % of the phalanges. Implant malposition was observed in the remaining 67 % of phalanges. CONCLUSION: The current design of the Ascension PyroCarbon PIP total joint can lead to malpositioning that we attribute to its incomplete accommodation of the morphology of the proximal and middle phalanx, the surgical challenges the design poses, or both acting together.