Revision of Articular Surface Replacement (ASR) Total Hip Arthroplasty: Correlation of Perioperative Data and Early Post-Revision Outcome Results.

The articular surface replacement (ASR) total hip arthroplasty (THA) showed accelerated failure rates due to adverse-reaction to metal debris (ARMD). Literature correlating preoperative with intraoperative revision findings respectively post-revision outcome results are rare. 30 of 99 available ASR THA were revised due to ARMD. Mean post-revision follow-up term was 2.3 years. In part, preoperative data did not correlate with intraoperative revision findings. ARMD was even found in asymptomatic patients with non-elevated ion levels. Postoperative pain and metal ions decreased significantly (P ≤ 0.016). Cobalt decreased faster than chrome. Patients with intraoperative pseudotumors, osteolysis or bilateral THA did not have higher pre- or postoperative ion values (P ≥ 0.053). Females showed higher postoperative chrome levels (P=0.031). One major post-revision complication (femoral nerve palsy) and one re-revision (late onset infection) occurred.

Implication of femoral stem on performance of articular surface replacement (ASR) XL total hip arthroplasty.

Taper junctions of large diameter metal-on-metal femoral heads and femoral stems were described as metal ion generator due to accelerated wear and corrosion. However, literature about the Articular Surface Replacement (ASR) total hip arthroplasty (THA) invariably deals with stems manufactured by DePuy Orthopedics (Warsaw, IN, USA). Nothing is known whether different stems with common 12/14 mm tapers affect failure rate or ion release. 99 ASR THA (88 patients) implanted with CoxaFit or ARGE Geradschaft stems (K-Implant, Hannover, Germany) were retrospectively analyzed. After a mean follow-up of 3.5 years revision rate was 24.5%, mostly due to adverse reaction to metal debris (ARMD). CT scan revealed component loosening in 10.3% and pseudotumoral lesions in 12.6%. Elevated ion concentrations (>7 µg/l) were found in 38.6%.

Conventional versus computer-assisted technique for total knee arthroplasty: a minimum of 5-year follow-up of 200 patients in a prospective randomized comparative trial.

In the literature, studies of computer-assisted total knee arthroplasty (TKA) after mid-term period are not conclusive and long-term data are rare. In a prospective, randomized, comparative study 100 conventional TKAs (group REG) were compared with 100 computer-assisted TKAs (group NAV). Minimum follow-up was 5years. No difference in implant failure was found with 1.1% in group NAV versus 4.6% in group REG (P=0.368). Group NAV showed a significantly less mean deviation of mechanical limb axis (P=0.015), more TKAs (90% versus 81% in group REG) were within 3° varus/valgus and a higher tibial slope and lateral distal femoral angle (LDFA) accuracy was found (P≤0.034). Clinical investigational parameters showed no differences (P≥0.058). Insall and HSS score total were also higher in group NAV (P≤0.016).

Scaphocapitate arthrodesis for treatment of scapholunate instability in manual workers.

PURPOSE: To assess the long-term efficacy of scaphocapitate arthrodesis for treatment of chronic scapholunate instability in high-demand patients. METHODS: We retrospectively analyzed the clinical and radiographic results of 20 manual workers who underwent scaphocapitate arthrodesis for chronic scapholunate instability at a mean follow-up of 10 years (range, 1-23 y). We measured range of motion and grip strength; pain on a scale of 0 to 5; Quick Disabilities of the Arm, Shoulder, and Hand score; and ability to return to work. We assessed radiographs for union, carpal height and alignment, signs of ulnar translation or radiocarpal arthritis, and hardware problems. RESULTS: At most recent follow-up, the arc of motion averaged 87° for flexion-extension and 41° for the radioulnar deviation. The postoperative average maximum grip strength was 21 kg, which was 60% of the opposite, normal wrist. Pain was significantly reduced. The average postoperative Quick Disabilities of the Arm, Shoulder, and Hand score was 19, and the return-to-work rate was 90%. Radiographic analysis showed union in all patients, improvement of carpal height and scaphoid angle, no evidence of ulnar translation, and a 30% rate of radiocarpal osteoarthritis. CONCLUSIONS: This report of long-term results demonstrates the efficacy of scaphocapitate limited carpal arthrodesis for the treatment of chronic rotatory subluxation of the scaphoid. We conclude that continued use of this procedure is warranted. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Effectiveness of four-corner arthrodesis with use of a locked dorsal circular plate.

BACKGROUND: Compared with traditional methods of fixation in four-corner arthrodesis, reviews of results using a dorsal circular plate (DCP) have identified higher complication rates. As the use of circular plate fixation for limited wrist arthrodesis was found to be a valuable concept per se and continued innovation and technical advancement are crucial to improve future treatment, changes in plate design were encouraged. QUESTIONS/PURPOSES: To further evaluate the use of DCP fixation in four-corner arthrodesis, we report the first results using a radiolucent, nonmetallic (polyetheretherketone), locked DCP for four-corner arthrodesis. METHODS: We retrospectively analyzed the clinical and radiographic results of 24 patients who underwent four-corner arthrodesis with a locked DCP at a minimum followup of 63 months (mean, 76 months; range, 63-91 months). There were nine women and 15 men, with a mean age of 53 years (range, 37-78 years) at the time of surgery. We evaluated ROM with a goniometer and grip strength with a dynamometer. Function was assessed using QuickDASH. Radiographs were evaluated for union, carpal alignment, and hardware problems. RESULTS: At latest followup, ROM averaged 66% and 77% of the uninjured side in flexion-extension and radioulnar deviation, respectively. Grip strength averaged 70% of the uninjured side. The average postoperative QuickDASH score was 19.11. Union was achieved by 22 of the 24 patients. CONCLUSIONS: Our data show four-corner arthrodesis with a radiolucent, nonmetallic, locked DCP is an effective procedure that allows stable primary fixation as a basis for good functional outcome, provided surgical technique and quality of bone graft are adequate. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Slotted acetabular augmentation, alone or as part of a combined one-stage approach for treatment of hip dysplasia in adolescents with cerebral palsy: results and complications in 19 hips.

BACKGROUND: Surgical correction for the challenging combined deformities in hip dysplasia associated with cerebral palsy remains controversial. The purpose of this study was to assess the efficacy and determine the role of slotted acetabular augmentation (SAA) for the treatment of neuromuscular hip dysplasia in comparison with other treatment options. METHODS: We retrospectively analyzed 19 dysplastic hips in 19 patients with cerebral palsy who underwent SAA, alone or as part of a combined 1-stage approach, consisting of soft tissue lengthening and/or a proximal femoral osteotomy, during a 20-year period. RESULTS: The mean age at the time of operation was 14 years and 7 months (range: 12 to 17 years and 11 months). All had a closed triradiate cartilage. In 13 hips, preoperative radiographs showed major aspheric femoral head deformities. All had subluxation or dislocation of the hip and severe acetabular dysplasia, associated with a painful hip in 15 patients. Before operation, the mean migration index was 64+/-18%, the mean Sharp angle was 51+/-4 degrees, and the mean center-edge angle was -4+/-13 degrees. On immediate postoperative radiographs, they were 3+/-5%, 35+/-5 degrees, and 42+/-11 degrees. At final follow-up, the average migration index was 10+/-8%, the mean Sharp angle was 35+/-6 degrees, and the mean center-edge angle was 39+/-13 degrees. Eleven hips required soft tissue lengthening and 5 hips had a proximal femoral osteotomy at the time of the shelf procedure. At the latest follow-up (mean duration: 5 years and 5 months), 16 of the 19 hips remained anatomically reduced. CONCLUSIONS: Our results suggest that SAA is a successful procedure to treat advanced neurogenic acetabular dysplasia with or without femoral head deformities in skeletally mature patients.

Bridging critical nerve defects through an acellular homograft seeded with autologous schwann cells obtained from a regeneration neuroma of the proximal stump.

Over the last decade, several models have investigated the usefulness of different biologic and/or synthetic matrices as alternatives to conventional nerve grafts. Still, axonal regeneration did not occur over longer (> 3 cm) distances. One problem may be that a growth-promoting environment not only includes physical cues but also a rich spectrum of different growth factors only provided by reactive Schwann cells. In the current study, we investigated whether a hybrid graft consisting of first-generation autologous Schwann cells seeded onto an acellular auto- or homograft can aid regeneration across a critical nerve defect in a rat model. In this paradigm, Schwann cells were not expanded in vitro but harvested from the proximal stump neuroma at the time of reconstruction and seeded into either an acellular homo- or autograft. Regeneration was then quantitated with functional muscle testing, regular histology, histomorphometry, and retrograde tracing techniques 12 weeks after reconstruction. Results showed successful regeneration over the entire distance regardless of whether Schwann cells were transplanted onto auto- or homologous acellular matrix. Schwann cells did populate both grafts; however, only sensory axons persisted through the entire distance. The functional outcome was dismal with no motor and poor sensory recovery. Control group C with homologous matrix only without Schwann cells showed no signs of directed axonal regeneration. Control group D with autologous reverse graft showed excellent recovery, as was expected. The present experiment sought to create a hybrid graft where the proximal stump neuroma is used as a biological resource for autologous Schwann cells that are seeded unto an acellular matrix, thus providing both physical and chemical support to regenerating axons. The results are encouraging in that successful regeneration was observed over the entire distance; however, only sensory axons had enough regenerative potential to also make end-organ contact. For motor axons, further refinements in conduit preparation have to be done.

Surgical treatment of AO type C distal humeral fractures: internal fixation with a Y-shaped reconstruction (Lambda) plate.

Although surgical repair is considered the standard treatment for intraarticular distal humeral fractures, most investigators have assessed its results using dual-plate fixation in 2 planes. The purpose of this study was to determine the functional outcome of open reduction and internal fixation of these complex fractures using Y-shaped reconstruction plates. We identified 17 patients who had operative treatment for Arbeitsgemeinschaft Für Osteosynthesefragen (AO) type 1, 3-C fractures using a Y-shaped Lambda plate (Zimmer, Warsaw, IN). Patients were recalled for follow-up that included recording of a complete history, physical examination, radiographic evaluation, and completion of a limb-specific questionnaire. The mean duration of follow-up was 37.3 months. The average loss of extension was 13 degrees , and the average arc of flexion-extension was 112 degrees . As determined by the Mayo Elbow Performance Index, 6 were graded excellent; 8, good; 3, fair; and none, poor. Surgical repair of intraarticular distal humeral fractures by open reduction and internal fixation with a Lambda plate is an effective procedure that allows for stable osteosynthesis without loss of reduction or fixation as a basis for good functional outcome.