Alexander P. Sah

Lateral unicompartmental knee arthroplasty through a medial approach. Study with an average five-year follow-up.

BACKGROUND Unicompartmental knee arthroplasty of the medial compartment has excellent long-term clinical outcomes. Arthritis isolated to the lateral compartment is much less common; subsequently, the clinical outcomes of the treatment of that condition are less frequently reported. Most commonly, the lateral compartment is approached through a lateral arthrotomy. The purpose of this study was to determine the mid-term results of lateral unicondylar replacement through a medial arthrotomy in patients with primary osteoarthritis or posttraumatic arthritis. METHODS From 1991 to 2004, forty-nine lateral unicompartmental knee arthroplasties were performed in forty-five patients by a single surgeon. One patient was excluded from the study because of a severe underlying neurologic condition. Lateral unicompartmental replacement was performed in thirty-eight knees with primary osteoarthritis and in ten knees with posttraumatic arthritis secondary to a tibial plateau fracture. Retrospective chart reviews and radiographic evaluations were performed, and Knee Society scores were determined. RESULTS The average Knee Society knee and function scores improved from 39 and 45 points, respectively, preoperatively to 89 and 80 points at an average of 5.2 years postoperatively. Preoperative alignment averaged 10 degrees of valgus, which was corrected to an average of 6.2 degrees of valgus postoperatively. There were no revisions and no notable soft-tissue complications. The mean postoperative knee and function scores were significantly better for patients with primary osteoarthritis (95 and 86 points, respectively) than they were for those with posttraumatic arthritis (74 and 65 points). CONCLUSIONS Lateral unicompartmental knee replacement through a medial approach provided durable and reliable short to mid-term results. This approach is safe, effective, and extensile, making it a viable alternative to a lateral approach. The outcomes of lateral unicompartmental replacement in patients with posttraumatic arthritis can be expected to be inferior to those in patients with primary osteoarthritis.

Correlation of plain radiographic indices of the hip with quantitative bone mineral density.

SummaryRadiographic parameters of the hip can be useful as an indication of bone mineral density at the femoral neck. Measurements available from routine hip radiographs were correlated with DXA values. Although radiographs are not a test for osteoporosis, measurements of cortical thickness provide information useful for referral for osteoporosis assessment.IntroductionPlain hip radiographs are widely used for evaluation of hip pathology in osteoarthritis. A purpose of this study was to determine whether there are relationships between radiographic parameters of bone structure and bone mineral density T-scores, as assessed by dual energy x-ray absorptiometry (DXA).MethodsPre-operative radiographs of 32 postmenopausal, osteoarthritic women undergoing hip arthroplasty were evaluated. Radiographic parameters including the Singh index, Dorr classification, canal-to-calcar ratio, and cortical thickness indices (CTI) were measured and compared with T-score, serum 25 hydroxyvitamin D levels, body mass index (BMI), and body weight.ResultsThe T-score at the femoral neck for type C bone was significantly lower than that of type A (p = 0.041). The CTIs were correlated positively with T-scores for anteroposterior radiographs (r = 0.5814, p = 0.0005), and for lateral radiographs (r = 0.571, p = 0.0006). A threshold for lateral CTI set at a value of ≤0.40 results in sensitivity of 0.85 and specificity of 0.79 to segregate the osteoporotic and non-osteoporotic patients.ConclusionFemurs with small radiographic cortical thickness indices had lower T-scores. Finding a radiographic hip cortical thickness index (LAT) with a value of ≤0.40 should be an alert for referral for osteoporosis evaluation and bone mineral density testing.

Interprosthetic fractures of the femur: treatment with a single-locked plate.

Interprosthetic fractures of the femur, those between an ipsilateral hip and knee arthroplasty, are challenging to treat secondary to limited bone available for fixation, osteopenic bone, a compromised intramedullary blood supply, and an often elderly patient population. From 2002 to 2006, 22 consecutive patients with an interprosthetic femur fracture were treated with a single-locking plate. Follow-up averaged 17.7 months, with fracture union achieved an average of 13.8 weeks postoperatively. All patients regained their preoperative ambulatory status and subjectively reported unchanged function of their hip and knee arthroplasties. Single-locked plating is an effective method of treatment of interprosthetic fractures of the femur. Emphasis on preservation of the soft tissue envelope and sufficient cortical purchase both above and below the fracture is of paramount importance.

Contemporary cruciate-retaining total knee arthroplasty with a pegged tibial baseplate. Results at a minimum of ten years.

BACKGROUND A total knee arthroplasty with a four-peg tibial baseplate is an uncommonly used contemporary design. Potential advantages of this baseplate include preservation of host bone, compatibility with minimally invasive techniques, and easier removal with revision techniques. The purpose of this study was to determine the long-term results of a contemporary total knee arthroplasty that included a four-peg tibial baseplate. METHODS From February 1995 to December 1996, 127 total knee arthroplasties were performed by one surgeon in 115 patients with an average age of seventy years. Clinical and radiographic evaluations were performed with use of the Knee Society scoring system at a minimum of ten years following replacement. Complications were identified by means of chart review and screening for readmission at surrounding institutions. RESULTS At the time of follow-up, at a minimum of ten years after the arthroplasty, thirty patients (with thirty-three involved knees) were documented to have died and four patients (with seven involved knees) could not be located. The next-of-kin of the patients who had died directly confirmed that the knee was unrevised at the time of death. Eighty-seven knees in eighty-one patients remained available for evaluation after a minimum of ten years of follow-up. Two knees had failed: one had a late infection at three years, and one had aseptic loosening at seven years. The rate of survival free of revision at ten years was 97%. Knee Society knee and function scores averaged 94 and 75 points, respectively. None of the remaining knees had radiographic evidence of loosening. CONCLUSIONS This study demonstrated excellent, durable clinical and radiographic results at a minimum of ten years after replacement with this cemented, modular, fixed-bearing, cruciate-retaining total knee prosthesis with a four-peg tibial baseplate. We believe that this design is an acceptable option for total knee arthroplasty.

Lateral Unicompartmental Knee Arthroplasty Through a Medial Approach

BACKGROUND Unicompartmental knee arthroplasty of the medial compartment has excellent long-term clinical outcomes. Arthritis isolated to the lateral compartment is much less common; subsequently, the clinical outcomes of the treatment of that condition are less frequently reported. Most commonly, the lateral compartment is approached through a lateral arthrotomy. The purpose of this study was to determine the midterm results of lateral unicondylar replacement through a medial arthrotomy in patients with primary osteoarthritis or posttraumatic arthritis. METHODS From 1991 to 2004, forty-nine lateral unicompartmental knee arthroplasties were performed in forty-five patients by a single surgeon. One patient was excluded from the study because of a severe underlying neurologic condition. Lateral unicompartmental replacement was performed in thirty-eight knees with primary osteoarthritis and in ten knees with posttraumatic arthritis secondary to a tibial plateau fracture. Retrospective chart reviews and radiographic evaluations were performed, and Knee Society scores were determined. RESULTS The average Knee Society knee and function scores improved from 39 and 45 points, respectively, preoperatively to 89 and 80 points at an average of 5.2 years postoperatively. Preoperative alignment averaged 10 degrees of valgus, which was corrected to an average of 6.2 degrees of valgus postoperatively. There were no revisions and no notable soft-tissue complications. The mean postoperative knee and function scores were significantly better for patients with primary osteoarthritis (95 and 86 points, respectively) than they were for those with posttraumatic arthritis (74 and 65 points). CONCLUSIONS Lateral unicompartmental knee replacement through a medial approach provided durable and reliable short to midterm results. This approach is safe, effective, and extensile, making it a viable alternative to a lateral approach. The outcomes of lateral unicompartmental replacement in patients with posttraumatic arthritis can be expected to be inferior to those in patients with primary osteoarthritis.

Dislocation Rate After Conversion from Hip Hemiarthroplasty to Total Hip Arthroplasty

BACKGROUND Revision hip arthroplasty is associated with a dislocation rate that is three to five times greater than the rate following primary hip replacement. Conversion of a hip hemiarthroplasty to a total hip replacement is a revision arthroplasty, but it differs from revisions of total hip arthroplasties because a native acetabulum is replaced and the subsequent prosthetic femoral head is smaller. It was our purpose to determine whether the risk of dislocation following conversion surgery is the same as or greater than that following revision total hip replacement. METHODS From 1994 to 2005, eighty-nine hemiarthroplasties were converted to a total hip arthroplasty in seventy-seven patients, and the results were compared with those of 115 first-time revision total hip replacements following a primary total hip replacement in 111 patients. A retrospective chart review was performed, and radiographic measurements were obtained. The patient demographics were similar between the two groups. The percentages of patients who had undergone revision of only the acetabular component as compared with both components as well as the percentages of those who had received a modular femoral stem as compared with a nonmodular stem were also similar between the two groups. RESULTS Postoperatively, the femoral head size and the positioning of the acetabular component were similar between the two groups. The acetabular components were significantly larger (p < 0.001) in the group in which a total hip arthroplasty had been revised because they required additional acetabular reaming for placement of a new component. There were significantly more dislocations after the conversion procedures (22%) than after the revisions of the total hip arthroplasties (10%) (p < 0.018). Within both groups, the size of the acetabular component, the intraoperative range of motion, and the positioning of the acetabular component were similar between the hips that dislocated and those that did not. However, smaller femoral head components were at greater risk for dislocation after conversion surgery than after revision of a total hip arthroplasty. CONCLUSIONS A substantial reduction of the size of the prosthetic femoral head is unique to conversion arthroplasty and appears to play a role in instability after the revision surgery. While the smallest heads dislocated in the conversion group, a larger femoral head did not ensure stability. The increased dislocation risk with conversion surgery requires emphasis on soft-tissue balance and avoidance of excessive downsizing of the femoral head in an attempt to maximize hip stability.

McKeever Hemiarthroplasty of the Knee in Patients Less Than Sixty Years Old

BACKGROUND Knee arthritis in the young patient is a challenging problem that may necessitate surgical treatment. We continue to perform hemiarthroplasty with a metallic tibial implant in selected young patients who, for various reasons, are not candidates for osteotomy, unicompartmental arthroplasty, or total knee arthroplasty. The purpose of the present study was to determine the minimum twelve-year results of this procedure in young patients. METHODS The original study group consisted of a consecutive series of twenty-four patients (twenty-six knees) who were managed with McKeever tibial hemiarthroplasty for the treatment of unicompartmental osteoarthritis of the knee. All patients were younger than sixty years of age at the time of the index procedure (average age, 44.6 years). During the study period, two patients died and one was lost to follow-up, leaving twenty-one patients (twenty-three knees) available for review. All patients were followed clinically for a minimum of twelve years or until revision. Knee Society knee and functional scores and Tegner scores were determined, and seven of the ten implants were evaluated radiographically. RESULTS Thirteen knees were revised at an average of eight years after the index procedures. All thirteen knees had an uncomplicated revision to either a unicompartmental arthroplasty or total knee arthroplasty. Ten retained implants were available for clinical review after an average duration of follow-up of 16.8 years. The mean Knee Society knee scores, functional scores, and Tegner scores, available for nine of these ten knees, were 80, 97, and 4.2, respectively. CONCLUSIONS We believe that the McKeever tibial hemiarthroplasty continues to be a reasonable surgical option for patients who are not candidates for osteotomy and are too young or too active for a unicompartmental or total knee arthroplasty.

Malignant transformation of synovial chondromatosis of the shoulder to chondrosarcoma. A case report.

Primary synovial chondromatosis is a proliferation of cartilaginous bodies within the synovial membrane, bursa, or tendon sheath. Historically, it has been characterized as a rare, monoarticular, benign arthropathy of uncertain etiology, typically involving a single large joint in a young adult. Males are affected more commonly than females1. The knee is involved most frequently, followed by the hip, elbow, shoulder, ankle, and wrist2-4; however, smaller joint involvement, including that of the spine, foot, and hand, has been reported5-8, as has involvement of the acromioclavicular, temporomandibular, and sternoclavicular joints9-12. The Massachusetts General Hospital tumor database contains eighty-six recorded cases of synovial chondromatosis; these cases include involvement of the knee (thirty-three cases), the hip (sixteen cases), the shoulder (eight cases), the ankle (seven cases), the foot (seven cases), the elbow (five cases), and miscellaneous locations (ten cases). Malignant degeneration of synovial chondromatosis into chondrosarcoma is a described, but extremely rare, event. We describe a unique case of synovial chondromatosis in the shoulder, which, following multiple recurrences with a repeatedly benign histologic appearance but abnormal results on deoxyribonucleic acid (DNA) flow cytometry, ultimately demonstrated histologic evidence of malignant transformation. The aneuploid DNA of this specimen distinguishes it from all other cases of synovial chondromatosis in the Massachusetts General Hospital tumor database. Our patient was informed that data concerning the case would be submitted for publication. A forty-seven-year-old man presented in February of 1999 with a two-year history of right shoulder pain and generalized shoulder discomfort that was most frequently related to activity. In addition, the patient reported that lying on the shoulder at night caused pain. The patient had not experienced trauma or any other inciting event, nor did he have any motor or sensory deficits or any additional …

2017 American College of Rheumatology/American Association of Hip and Knee Surgeons Guideline for the Perioperative Management of Antirheumatic Medication in Patients With Rheumatic Diseases Undergoing Elective Total Hip or Total Knee Arthroplasty

This collaboration between the American College of Rheumatology and the American Association of Hip and Knee Surgeons developed an evidence‐based guideline for the perioperative management of antirheumatic drug therapy for adults with rheumatoid arthritis (RA), spondyloarthritis (SpA) including ankylosing spondylitis and psoriatic arthritis, juvenile idiopathic arthritis (JIA), or systemic lupus erythematosus (SLE) undergoing elective total hip (THA) or total knee arthroplasty (TKA).

Unicompartmental knee arthroplasty in octogenarians: survival longer than the patient.

The unicompartmental knee arthroplasty continues to gain popularity as a viable treatment option for disease isolated to one compartment. It has been reported to provide decreased perioperative morbidity, faster recovery, and excellent long- term survival. We hypothesized that the unicompartmental knee arthroplasty is durable enough to benefit octogenarians, and may be a viable alternative to total knee arthroplasty as the definitive treatment of localized arthritis in this age group. From 1978 to 1990, 28 consecutive patients (38 knees) 80 years or older had unicompartmental knee arthroplasties. Knee Society knee and function scores improved at an average of 4 years followup (range, 2-9 years). Family members reported 90% patient satisfaction regarding expectations and desire to have the surgery again. The mean postoperative survival was 11.9 years, and only two of the 38 knees (5%) required surgical intervention. At final followup, 25 patients had died with all but one patient having the index unicompartmental knee arthroplasty in place and functioning well. Of the three living patients, one required surgery for femoral component fracture 10 years after the index procedure. The unicompartmental knee arthroplasty can be expected to provide reliable and durable results in certain octogenarians, and should be regarded as a definitive treatment option in appropriated selected patients of this age group.Level of Evidence: Level IV Therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.