Clinical and Functional Outcomes: Primary Constrained Condylar Knee Arthroplasty Compared With Posterior Stabilized Knee Arthroplasty.

INTRODUCTION: Constrained condylar knee (CCK) prostheses are commonly used in difficult primary total knee arthroplasty and revision total knee arthroplasty. We postulate that the use of CCK prostheses in primary knee arthroplasty may result in decreased range of motion but with better patient-reported functional scores compared with primary posterior stabilized (PS) knee prostheses because of increased varus and valgus stability from increased constraint. METHODS: We conducted a case-control study using prospectively collected data on functional outcome scores and range of motion preoperatively and at 6 months and at 2 years. Thirty-eight patients with primary CCK arthroplasty were matched with 38 patients with primary PS knee arthroplasty treated by a single surgeon. Institutional review board approval was obtained. Analysis was done using the independent t-test. RESULTS: Total 76 patients with 61 (80.3%) female patients, 30 (39.5%) left knees, and 9 (11.8%) valgus knees. There was no significant difference in preoperative age (CCK arthroplasty 70.7 ± 6.0 years versus PS knee arthroplasty 68.5 ± 5.2 years; P < 0.085), body mass index (27.2 ± 4.4 versus 26.3 ± 5.2; P < 0.44), Oxford Knee Score (35.8 ± 7.8 versus 36.0 ± 7.6; P < 0.92), and Medical Outcomes Study 12-Item Short Form (SF-36) scores and knee extension (8.0° ± 6.7° versus 7.7° ± 7.6°; P < 0.84). There was no significant difference in preoperative knee flexion (106.0° ± 22.9° versus 117.3° ± 20.1°; P < 0.026). There was no significant difference in 6-month knee extension (4.5° ± 6.8° versus 4.1° ± 4.5°; P < 0.80), knee flexion (110.5° ± 15.8° versus 110.9° ± 15.5°; P < 0.92), Oxford Knee Score (18.9° ± 3.4° versus 20.1° ± 5.3°; P < 0.27), and SF-36 scores. There was no significant difference in 2-year knee extension (1.8° ± 5.7° versus 1.5° ± 4.0°; P < 0.82), knee flexion (111.3° ± 13.6° versus 115.0° ± 16.5°; P < 0.30), Oxford Knee Score (18.5° ± 3.7° versus 18.2° ± 4.2°; P < 0.77), and SF-36 scores. CONCLUSION: The use of CCK prostheses in primary knee arthroplasty gives similar clinical and functional outcomes at 2 years as those of PS knee prostheses, despite increased constraint.

Outcomes following total knee arthroplasty with CT-based patient-specific instrumentation.

PURPOSE: A 24-month prospective follow-up study was carried out to compare perioperative clinical outcomes, radiographic limb alignment, component positioning, as well as functional outcomes following total knee arthroplasty (TKA) between patient-specific instrumentation (PSI) and conventional instrumentation (CI). METHODS: Ninety consecutive patients, satisfying the inclusion and exclusion criteria, were scheduled to undergo TKA with either PSI or CI. A CT-based PSI was used in this study, and a senior surgeon performed all surgeries. Patients were clinically and functionally assessed preoperatively, 6 and 24 months post-operatively. Perioperative outcomes were also analysed, including operating time, haemoglobin loss, the need for blood transfusion, length of hospitalisation, and radiographic features. RESULTS: At 24-month follow-up, clinical and functional outcomes were comparable between the two groups. PSI performed no better than CI in restoring lower limb mechanical alignment or improving component positioning. There were no differences in operating time, haemoglobin loss, transfusion rate, or length of hospitalisation between PSI and CI. CONCLUSION: No significant clinical benefit could be demonstrated in using PSI over CI after 24 months, and routine use of PSI is not recommended in non-complicated TKA. LEVEL OF EVIDENCE: II.

Multiple locations of nerve compression: an unusual cause of persistent lower limb paresthesia.

A paucity of appreciation exists that the "double crush" phenomenon can account for persistent leg symptoms even after spinal neural decompression surgery. We present an unusual case of multiple locations of nerve compression causing persistent lower limb paresthesia in a 40-year old male patient. The patient's lower limb paresthesia was persistent after an initial spinal surgery to treat spinal lateral recess stenosis thought to be responsible for the symptoms. It was later discovered that he had peroneal muscle herniations that had caused superficial peroneal nerve entrapments at 2 separate locations. The patient obtained much symptomatic relief after decompression of the peripheral nerve. The "double crush" phenomenon and multiple levels of nerve compression should be considered when evaluating lower limb neurogenic symptoms, especially after spinal nerve root surgery.

Positive ProbeTec tests in fresh specimens from malignant musculoskeletal tumors: a case series.

OBJECTIVE: To report a case series of patients with high-grade musculoskeletal sarcomas whose biopsies of fresh specimens yielded positive Becton Dickinson ProbeTec tests, in addition to confirming diagnoses of high-grade sarcomas. METHODS: Fresh biopsies of high-grade musculoskeletal sarcomas were subjected to ProbeTec tests. RESULTS: The biopsies of three Chinese patients aged 65, 49 and 78 years with high-grade musculoskeletal sarcomas had positive Becton Dickinson ProbeTec tests. These patients' overall clinical pictures were not consistent with active tuberculous infections, which suggested that the ProbeTec test results were false-positives. The reason for this is not known but it is postulated that there is homology between the primers used for the ProbeTec test and the molecular properties of high-grade sarcomas. CONCLUSION: With the increasing use of the ProbeTec test in clinical practice, fellow surgeons and pathologists are encouraged to be aware of this phenomenon.

The influence of primary site on outcomes in leiomyosarcoma: a review of clinicopathologic differences between uterine and extrauterine disease.

BACKGROUND: Leiomyosarcomas (LMS) comprise 25% of soft tissue sarcomas. Recent reports suggest differences in treatment outcomes between uterine (uLMS) and extrauterine (eLMS) disease that may reflect distinct disease biologies. We sought to identify prognostic factors in LMS and clinicopathologic differences between uLMS and eLMS. METHODS: This is a single-center retrospective study evaluating 97 eligible patients treated for LMS between 2002 and 2010. RESULTS: Median follow-up was 21.2 months. uLMS affected 53% of patients, and was less common beyond age 60 years compared with eLMS (10% vs. 37%, P = 0.002). Seventy-two percent of patients presented with nonmetastatic disease. Of these, 94% underwent curative surgery, among whom more uLMS patients achieved negative surgical margins (90% vs. 45%, P = 0.003). There were no significant differences in adjuvant therapy use and relapse patterns between uLMS and eLMS. Half of metastatic patients received palliative chemotherapy, among whom 76% received anthracycline-based chemotherapy in first line to which response rate was 31%. Median overall survival was 45.2 months, 49.8 months in uLMS, and 40.5 months in eLMS (P = 0.294). Among patients without metastases, median survival was 60.8 months (77.3 vs. 48.1 mo in uLMS and eLMS, respectively, P = 0.194). In metastatic disease, median survival was 20.7 months (22.0 vs. 17.5 mo in uLMS and eLMS, respectively, P = 0.936). Advanced disease stage, bone metastases and lack of metastasectomy prognosticated for inferior survival. CONCLUSIONS: While demonstrating interesting clinicopathologic differences, the evidence for uLMS and eLMS being biologically distinct remains inconclusive. Disease stage is prognostically most important in LMS.

Randomized controlled trial comparing the radiologic outcomes of conventional and minimally invasive techniques for total knee arthroplasty.

The objective of this study was to compare the radiologic outcomes of total knee arthroplasty using the conventional technique with those using minimally invasive surgery (MIS) techniques. Ninety patients were randomized to undergo conventional (control), MIS mini-incision mid-vastus (mini), or MIS side-cutting (side cut) techniques for their total knee arthroplasty. Long-leg radiographs were assessed postoperatively. The mean overall limb varus alignments were 1.03 degrees (SD, 2.58 degrees ) for the control group, 0.87 degrees (SD, 2.96 degrees ) for the mini group, and 0.37 degrees (SD 4.27 degrees ) for the side cut group. The mean overall limb alignments within +/-3.0 degrees varus/valgus were 83.3%, 83.3%, and 56.7%, respectively. Femoral implant placement (P = .028) and overall limb alignment (P = .024) in the side cut group were significantly poorer as compared with those in the control group. The side cut group also had more outliers in the coronal plane. Results were comparable between the mini and control groups. The side cut technique appears to affect the accuracy of implant placement.

Results, experience and technical points learnt with use of the SKy Bone Expander kyphoplasty system for osteoporotic vertebral compression fractures: a prospective study of 40 patients with a minimum of 12 months of follow-up.

To describe our centre's results, experience and technical points learnt with the SKy Bone Expander System for osteoporotic vertebral compression fractures (VCFs). Forty consecutive patients with painful single level T12 or L1 osteoporotic VCF who had failed conservative management for more than 3 months had 40 single level SKy Bone Expander kyphoplasties performed. Using local anaesthesia with patients in a prone, hyper-lordotic position, a unilateral, percutaneous, intra-pedicular approach was employed. Once correctly positioned, the SKy Bone Expander was expanded, creating a void. It was subsequently contracted, removed and bone cement injected. Pre-kyphoplasty and 12-month post-kyphoplasty radiological and functional outcomes were recorded. Statistical analysis was by Wilcoxon Signed Ranks Test. Median percentage increase in anterior, middle and posterior vertebral body heights at 12-month post-operative was 51.25% [inter-quartile range (IQR) 17.21-93.22], 52.29% (IQR 26.50-126.17) and 9.84% (IQR 4.94-19.26) respectively, while median percentage decrease in kyphotic angle was 30.77% (IQR 17.06-46.61). There was no significant vertebral body correction loss at 12-month post-operative. Visual analogue score, North American Spine Society and Short Form-36 scores for physical functioning and bodily pain scores improved by medians of 5.0 (IQR 3.0-8.0), 1.45 (IQR 0.68-2.90), 20.5 (IQR 0.0-40.8) and 10.0 (IQR 0.0-20.0) respectively. All P-values were <0.001. There were eight adjacent/remote level VCFs, three cases of cement extravasation and one case of the SKy Bone Expander being unable to be contracted and withdrawn from the vertebral body. It was left in situ. This is the first reported incidence of such a complication. The SKy Bone Expander System appears to be a viable alternative to balloon tamp kyphoplasty. Important technical considerations include proper device positioning within the vertebral body before expansion, single use of devices, familiarity with salvage procedure and injection of bone cement under close image intensifier guidance to prevent cement extravasation.