Jonathan R. Danoff

Redefining the Acetabular Component Safe Zone for Posterior Approach Total Hip Arthroplasty

BACKGROUND Acetabular component orientation influences joint stability in total hip arthroplasty (THA). The purpose of this study was to evaluate the effect of cup orientation and other variables on hip dislocation risk and to define a posterior approach specific safe zone. METHODS A cohort of 1289 posterior approach primary THA cases was prospectively followed and component position measured radiographically. RESULTS Cup malposition, with respect to the Lewinnek safe zone, was an independent risk factor for dislocation (OR1.88). Modifying the anteversion safe zone limits to 10-25° strongly predicted increased dislocation risk (OR2.69). No dislocations occurred within a zone defined by a circle centered at 41.4° abduction and 17.1° anteversion, radius 4.3°. CONCLUSION Utilizing a posterior approach specific safe zone of 10-25° anteversion and 30-50° abduction may minimize THA dislocations. LEVEL OF EVIDENCE Level III.

The Use of Thermal Shrinkage for Scapholunate Instability

Scapholunate interosseous ligament (SLIL) instability is the most common form of carpal instability. There is a lack of consensus among hand surgeons as to the appropriate treatment of various stages. This article reviews the background and results of thermal treatment of predynamic instability of the SLIL. Case examples are discussed as well as a series of patients treated with our protocol for this injury.

The Management of Kienböck Disease: A Survey of the ASSH Membership

Background The purpose of this study was to determine the current trends and common practices for the treatment of Kienböck disease at different stages. Question/Purpose To determine the current trends and common practices by hand surgeons for the treatment of Kienböck disease. Methods A survey with hypothetical Kienböck disease cases stratified by the Lichtman staging system was distributed to the American Society for Surgery of the Hand (ASSH) members. Questions and responses reflected common treatment strategies. Results Of a total of 375 worldwide respondents, preferred treatments of Kienböck disease were as follows: for Stage I disease, an initial trial of splinting was favored (74%), followed by radial shortening osteotomy for continued symptoms. For Stage II disease, 63% of surgeons preferred surgical intervention, particularly radial shortening osteotomy. For Stage IIIa with negative ulnar variance, 69% chose radial shortening osteotomy. Responses were heterogeneous for Stage IIIa Kienböck with positive variance, and capitate shortening osteotomy and vascularized bone grafting were preferred. Salvage procedures predominated for Stage IIIb disease, including proximal row carpectomy (PRC; 42%), intracarpal arthrodesis (21%), and total wrist fusion (10.7%). Similarly, Stage IV disease was treated by 87% of respondents by either PRC or wrist fusion. Without regard to stage of disease, 90% of participants reported using the same Lichtman staging to guide treatment and would also alter treatment strategy based upon ulnar variance. Conclusions Most respondents used Lichtman staging and ulnar variance to guide treatment decisions. Results indicate that the most common surgical treatments were radial shortening osteotomy for early disease and PRC in later stages. Level of Evidence Level IV, Economic/Decision Analysis.

Dorsoradial ligament imbrication for thumb carpometacarpal joint instability.

Dorsoradial ligament imbrication is a direct and effective alternative to ligament reconstruction or metacarpal osteotomy in patients with symptomatic thumb carpometacarpal (CMC) joint instability. This procedure is performed by imbricating either the trapezial or the metacarpal attachment of the dorsoradial ligament with the use of a suture anchor. The procedure is indicated in the setting of chronic hyperlaxity or instability of the thumb CMC joint. Significant arthritic changes in the thumb CMC joint are a contraindication for this procedure. We present our technique along with an anatomic dissection to demonstrate the ligament and surgical procedure on an anatomic specimen. We also present results from 3 patients who underwent this technique with images and clinical results for 3 patients with long-term follow-up. Level of Evidence: Level IV—Therapeutic.

The Cemented Unipolar Prosthesis for the Management of Displaced Femoral Neck Fractures in the Dependent Osteopenic Elderly

BACKGROUND Significant variability exists across orthopedic surgeons in the management of the displaced femoral neck fracture in the elderly patient (>75 years old). These patients tend to be less healthy, have inferior bone quality, and gait instability leading to increased risk of periprosthetic fracture, compromised implant fixation, dislocation, and need for revision. The surgeons goals should be to restore mobility while eliminating pain and need for reoperation. METHODS In this review article, we examine the best available evidence in the literature to determine which strategy achieves optimal outcomes. We examine outcome studies comparing use of hemiarthroplasty and total hip arthroplasty, unipolar and bipolar hemiarthroplasty, and cemented vs cementless fixation of femoral stems. RESULTS AND CONCLUSIONS For the active, healthy, and lucid patient, or one who has preexisting groin pain, who sustains a displaced femoral neck fracture, the literature supports a total hip arthroplasty. Patients sustaining a displaced femoral neck fracture and who are less active, have decreased bone mass, and are at increased risk of falls would benefit most from a device that optimally balances the need for revision surgery, restores ambulation, and eliminates pain. Thus, the current evidence favors cemented, unipolar hemiarthroplasty for the dependent osteopenic elderly patient with a displaced femoral neck fracture.

Revision Wrist Arthroscopy after Failed Primary Arthroscopic Treatment

UNLABELLED Background The etiologies and outcomes of cases of failed therapeutic wrist arthroscopy have not been well-described to date. Purpose The purposes of this study were to identify common preventable patterns of failure in wrist arthroscopy and to report outcomes of a series of revision arthroscopy cases. Patients and Methods Retrospective review of 237 wrist arthroscopies revealed 21 patients with a prior arthroscopy for the same symptoms, of which 16 were assessed by questionnaires and physical exam for this study. Results Six of sixteen patients (38%) had unrecognized dynamic ulnar impaction after débridement of triangular fibrocartilage complex (TFCC) tears, which resolved with arthroscopic wafer resection. Five (31%) had persistent distal radioulnar joint (DRUJ) instability after initial treatment of TFCC tears, requiring arthroscopic repair at revision. Four (25%) experienced diffuse dorsal wrist pain initially diagnosed as TFCC tears, but dynamic scapholunate ligament injuries were found and addressed with radiofrequency (RF) shrinkage at reoperation. Two (13%) required further resection of the radial styloid, after initial débridement was insufficient to correct radioscaphoid impingement. At a mean of 4.8 years after repeat arthroscopy (range, 1.5-13.4 years), this cohort had significant improvements in pain and satisfaction with outcomes after revision arthroscopy. Conclusions The most common indications for repeat wrist arthroscopy were ligamentous instability (of the DRUJ or scapholunate ligament) and osteoarthritis (from dynamic ulnar impaction or radioscaphoid impingement). Although revision wrist arthroscopy may yield acceptable outcomes, careful assessment of stability and cartilage wear at index procedure is crucial. LEVEL OF EVIDENCE  Level IV Therapeutic.

A novel arthroscopic technique utilizing bone morphogenetic protein in the treatment of Kienböck disease.

Kienböck disease, first described in 1910, is osteonecrosis of the carpal lunate and has been associated with ulnar minus variance. Numerous joint leveling procedures have been developed for patients with ulnar-negative variance to decrease forces transmitted across the lunate. The basis of operative treatment is the presence or absence of advanced osteoarthritis associated with fragmentation of the carpal lunate and capitate descent. Bone morphogenetic proteins (BMPs) have been utilized successfully as adjunctive treatment in fracture healing and recently in the surgical treatment of a patient with Lichtman stage IIIA Kienböck disease. Arthroscopy is an available tool in assessing cartilage injury and coupled with the use of BMP may be of benefit in patients with ulnar-neutral or ulnar-negative wrists who have not progressed to severe arthritis and capitate descent. We report a novel arthroscopic technique in which a stage IIIA and IIIB carpal lunate osteonecrosis is treated by curettage and grafting with an admixture of autologous radial cancellous bone marrow graft and BMP-2.

Augmentation of Fracture Healing Using Soft Callus.

Objectives: This study sought to investigate the effect of soft callus removal and reapplication in a rat closed femur fracture model. We hypothesized that removing soft callus will impair fracture healing, whereas reapplication will facilitate healing. Methods: A closed midshaft femur fracture was created in 78 rats and stabilized with an intramedullary wire. Seven days later, rats were equally divided and fractures surgically exposed. In the control group, no callus was removed, whereas in the callus removal group CR(−) group, the callus was removed and in the callus replaced group CR(+), callus was removed and replaced. Half of the rats were killed at 4 and 7 weeks. Fracture healing was graded with radiographs and callus volume measured with micro-CT. Mechanical torsion properties were measured, and histologic analysis was conducted. Results: At both end points, evidence of delayed healing was found on radiographs and micro-CT in CR(−) rats (P = 0.0001), whereas CR(+) rats showed normal fracture healing compared with controls. The normalized callus volume was similar in all groups at both end points. At 7 weeks, the maximum stiffness in CR(−) rats was 68% less than control (P = 0.0001). Stiffness increased 55% in CR(+) rats from CR(−) rats (P = 0.0017). Histology supported our findings with complete endochondral ossification in CR(+) rats but wide areas of hyaline cartilage in CR(−) rats at 7 weeks. Conclusions: Removal of soft callus in a rat model delays fracture healing at early and late time points, whereas replacement mitigates these negative consequences. Replacing the soft callus should be considered in all osteosynthesis procedures.

Risk factors for conversion surgery to total hip arthroplasty of a hemiarthroplasty performed for a femoral neck fracture

INTRODUCTION The purpose of this study was to determine risk factors for conversion to total hip arthroplasty (THA) in patients originally treated with hemiarthroplasty (HA) for displaced femoral neck fractures. METHODS In this case-controlled study, we identified 54 patients who were treated with HA for femoral neck fracture (FNF) who subsequently underwent conversion to THA at our institution between 2003 and 2013. We randomly selected 142 control patients who underwent HA for a displaced FNF without conversion surgery during the same time period. We compared demographic data, implant parameters, and radiographic data between the groups to identify risk factors for conversion surgery. RESULTS In the univariate analysis, younger age at index surgery (mean 75 vs. 80 years, p = 0.006), higher body mass index (26.1 vs. 23.7, p = 0.031), bipolar prosthesis (20% vs. 36%, p = 0.024), absence of dementia (6% vs. 23%, p = 0.01), increased leg length compared to contralateral limb (6.5 mm vs. 0.2 mm, p<0.001), and increased HA femoral head size compared to the contralateral femoral head (2.7 mm vs. 1.5 mm, p = 0.02) were associated with a significantly increased risk of conversion surgery. In the multivariate logistic regression, decreased age at index surgery, no dementia, use of a bipolar head, and increased leg length discrepancy (LLD) were associated with risk of conversion. CONCLUSIONS Patient characteristics, including younger age, increased BMI, and absence of dementia can lead to increased risk for conversion of HA to THA. Intraoperative considerations of head size and increase in ipsilateral LLD may increase the risk of conversion surgery. These factors should be considered by surgeons who employ HA for displaced FNFs.

Arthroscopic Wrist Debridement and Radial Styloidectomy for Advanced Scapholunate Advanced Collapse Wrist: Long-term Follow-up

Background: Symptomatic stage 2 or 3 scapholunate advanced collapse (SLAC) wrist is aggressively treated with salvage procedures, such as proximal row carpectomy or partial wrist fusion with resultant pain relief but limited motion. We hypothesize that arthroscopic synovectomy, radial styloidectomy, and neurectomy will preserve wrist motion, relieve pain, and delay or avoid salvage procedures. Methods: We evaluated outcomes in 13 wrists through questionnaires and 11 of these through additional physical examination at a mean follow-up of 5.0 years. Eight wrists were stage 2 and 5 were stage 3. Data at final follow-up included mobility/strength measurements, subjective outcome scores (Disabilities of the Arm, Shoulder, and Hand [DASH] and visual analog scale [VAS] pain), patient satisfaction, and return to work statistics. Results: Patients had an average flexion-extension arc of 88.0° in the treated wrist and an average grip strength that was 95.0% of the contralateral side. No patients required revision surgery at follow-up. The 13 wrists reported an average DASH score of 16.4 and mean VAS pain score at rest and with activity of 17.9 and 31.6, respectively. All patients working prior to the procedure (n = 8) were able to immediately return to work. In all, 84.6% of patients were satisfied. Conclusions: The procedure studied may have advantages in relieving pain, while preserving wrist motion for SLAC stage 2 or 3 disease. This procedure does not preclude future salvage procedures in those patients with severe disease who prefer to maintain wrist motion for the short term. Patients experience good functional outcomes with the majority experiencing a reduction in pain with the ability to return to work.