A systematic approach to predicting the risk of unicompartmental knee arthroplasty revision.

OBJECTIVE: Unicompartmental knee arthroplasty (UKA) revision is usually due to the degenerative degree of knee articular osteochondral tissue in the untreated compartment. However, it is difficult to simulate the biomechanical behavior on this tissue accurately. This study presents and validates a reliable system to predict which osteoarthritis (OA) patients may suffer revision as a result of biomechanical reasons after having UKA. DESIGN: We collected all revision cases available (n = 11) and randomly selected 67 UKA cases to keep the revision prevalence of almost 14%. All these 78 cases have been followed at least 2 years. An elastic model is designed to characterize the biomechanical behavior of the articular osteochondral tissue for each patient. After calculated the force on the tissue, finite element method (FEM) is applied to calculating the strain of each tissue node. Kernel Ridge Regression (KRR) method is used to model the relationship between the strain information and the risk of revision. Therefore, the risk of UKA revision can be predicted by this integrated model. RESULTS: Leave-one-out (LOO) cross-validation (CV) is implemented to assess the prediction accuracy. As a result, the mean prediction accuracy is 93.58% for all these cases, demonstrating the high value of this model as a decision-making assistant for surgical plaining of knee OA. CONCLUSIONS: The results of this study demonstrated that this integrated model can predict the risk of UKA revision with theoretically high accuracy. It combines bio-mechanical and statistical learning approach to create a surgical planning tool which may support clinical decision in the future.

Successful symptomatic treatment of melorheostosis with nifedipine.

Melorheostosis is an unusual sclerotic dysplasia of bone. We describe a patient with melorheostosis who showed improvement in pain and vasomotor function after treatment with nifedipine. Peripheral vascular disturbances may be responsible for the pain associated with this disorder and vascular abnormalities could possibly be related to the pathogenesis of this disease.

Decreased production of suppressive-B-cell factor by synovial membrane B-lymphocytes in rheumatoid arthritis.

Suppressive-B-cell factor (SBF) is an autoregulatory B-cell lymphokine produced by heat-aggregated-IgG stimulated B-lymphocytes which suppresses polyclonal immunoglobulin production. SBF production by rheumatoid arthritis (RA) patients' peripheral blood B-lymphocytes inversely correlates with disease activity and in vitro rheumatoid factor production. To further define the role of SBF in the pathogenesis of RA, the present study measured SBF production by surgically-obtained synovial membrane mononuclear leukocytes. SBF production by RA synovial leukocytes was similar to the levels previously described for RA peripheral blood leukocytes. Both RA and osteoarthritis (OA) synovial leukocytes produced significantly less SBF than leukocytes obtained from otherwise healthy patients with plica. OA patients produced less SBF than RA patients, but the difference was not statistically significant. SBF values for combined RA patients and controls with OA or plica correlated with the degree of histological plasma cell infiltration providing further evidence for SBF production by cells of the B-lymphocyte lineage. Depletion studies also demonstrated that synovial SBF was produced by B-lymphocytes. The molecular weight (34,000) of synovial SBF was similar to the molecular weight of peripheral blood SBF. Decreased SBF production by RA synovial B-lymphocytes is a functional abnormality in RA which may contribute to the perpetuation of synovial rheumatoid factor production and chronic synovial inflammation.

Thermoregulatory abnormalities of the foot.

Thermoregulatory abnormalities are well known but poorly understood phenomena. Pathologic alterations of microvascular blood flow occur in a variety of diseases of the foot, and often cause severe functional impairment. The structure, function, and methods for testing thermoregulatory abnormalities are reviewed. Pathologic manifestations of abnormal thermoregulation are also discussed.

Arthroscopic excision of the radial head: Clinical outcome in 12 patients with post-traumatic arthritis after fracture of the radial head or rheumatoid arthritis.

PURPOSE: We performed arthroscopic radial head excision in a series of patients with either post-traumatic arthritis after a radial head fracture or rheumatoid arthritis of the elbow as an expanded indication for elbow arthroscopy. The purpose of the study was to critically examine the results of arthroscopic chondroplasty of the radial head to determine the safety and effectiveness of the procedure. TYPE OF STUDY: Outcome study and retrospective analysis. METHODS: From 1990 to 1997, arthroscopic radial head resection was performed in 12 patients with either post-traumatic arthritis (n = 10, Mason type II or III) or with rheumatoid arthritis (n = 2). Functional outcome and radiographs were analyzed after a mean follow-up period of 39 months (range, 12 to 97 months). Elbow arthroscopy was performed using a standardized technique. The anterior three quarters of the radial head and 2 to 3 mm of the radial neck were resected with the abrader in the anterolateral portal and the arthroscope in the proximal medial portal. For resection of the posterior portion of the radial head, the abrader may be transferred to the mediolateral portal. This permits resection of the remnants of the radial head posteriorly and also at the proximal radioulnar joint. RESULTS: Preoperatively, patients lacked 23 degrees (range, 5 degrees to 40 degrees ) of extension of the elbow on average. Mean flexion was 111 degrees (range, 60 degrees to 145 degrees ). Patients had unrestricted pronation (limitation of 5 degrees in 2 patients). Two patients had a lack of supination of 15 degrees and 30 degrees. Mean follow up was 39 months (range, 12 to 97 months). Postoperatively, patients lacked 9 degrees (range, 0 degrees to 20 degrees ) of extension of the elbow on average. Mean flexion was 136 degrees (range, 90 degrees to 150 degrees ). No patient had subjective or objective evidence of instability of the elbow. All patients except one reported significant improvement in pain relief and complete relief of mechanical symptoms. CONCLUSIONS: This technically demanding surgical procedure should be reserved for situations of persistent, restricted range of motion and chronic pain. Arthroscopic radial head resection combined with arthroscopic synovectomy relieves elbow stiffness. The surgeon is able to deal with the intrinsic joint pathology, as well as with accompanying symptoms such as synovitis, capsular contracture, or loose bodies.

Arthroscopic surgery of the wrist.

This article has presented the technique of wrist arthroscopy, reviewed the principles and strategy of arthroscopy, described arthroscopic wrist anatomy, compared wrist arthroscopy and arthrography, and illustrated several cases of arthroscopic wrist surgery. We have not discussed indications. More cases and careful follow-up studies must be performed before definite recommendations can be made. The authors are encouraged by their early achievement and believe that the future of arthroscopy of the wrist is exciting. The hand surgeon who performs wrist arthroscopy considers wrist patients to be among the most interesting. The authors believe that arthroscopic surgery will become as important diagnostically and therapeutically in the wrist as it has in the knee.

Arthroscopic treatment of Panner's disease.

Panner's disease, or osteochondrosis of the capitellum, may actually be a continuum of disorders. In the past, such lesions were treated conservatively with surgery as a final option. With the advent of arthroscopy, a diagnosis can be made, and treatment with limited invasiveness instituted. This article reviews the diagnostic and therapeutic advantages of arthroscopic techniques in the treatment of Panner's disease.

Arthroscopy of the wrist in athletes.

Athletes are prone to a variety of pathologic conditions of the wrist. Wrist arthroscopy has become an effective tool in the diagnosis and treatment of athletes with wrist problems. Because it is minimally invasive, wrist arthroscopy often allows early return to training and competition. This article discusses the causes of wrist problems in athletes, their classification, the portals, and the intra-articular anatomy in the context of arthroscopic intervention.

The landscape of meniscal injuries.

This article analyzes meniscal injuries seen in 10,117 knee arthroscopies. The information was compiled by a centralized data base at Surgical Data Management. The study suggests two patterns of meniscal injuries, degenerative and traumatic. Injuries to the menisci occurring with an associated anterior cruciate injury, radial tears, and tears within 3 mm of the meniscosynovial junction are associated with a younger and more active patient who is more likely to sustain a traumatic or sports-related injury. Tears described as complex, horizontal cleavage, and flap tears are associated with an older age group and follow a more degenerative pattern.

Principles of arthroscopy and wrist arthroscopy equipment.

This article provides an overview of the history of wrist arthroscopy. Following this, the basic principles of wrist arthroscopy are presented. In the final portion of the chapter, the equipment and instrumentation used in wrist arthroscopy are discussed, including traction apparati, arthroscopes, mechanical infusion systems, hand instruments, and shavers.

Arthroscopy of the elbow.

Elbow arthroscopy is, to a degree, technically demanding. A complete knowledge of the regional anatomy of the elbow is essential. The technical expertise of the arthroscopist continues to improve, and sophistication of equipment continues to increase. These clear the way for new indications of elbow arthroscopy. It is obvious that with sound judgment in regard to case selection, with caution, and with prone patient positioning, arthroscopy can effectively address many pathologic conditions of the elbow in a minimally invasive fashion.

The role of operative arthroscopy for the diagnosis and treatment of lesions about the distal ulna.

Operative arthroscopy of the wrist compliments the physical examination and radiographic imaging to improve diagnosis and treatment of lesions about the distal ulna. This article reviews the relevant anatomy, biomechanics, and classification of acute and degenerative lesions of the triangular fibrocartilage complex (TFCC). Minimally invasive diagnostic and management techniques for TFCC tears are described in detail.

Endoscopic carpal tunnel release. The Agee technique.

The authors describe their technique for endoscopic carpal tunnel release using the Agree device. Technical points, illustrations, and postoperative regimen are provided.

Thumb reconstruction--an algorithm.

A patient-oriented treatment algorithm was developed to place in perspective the multiple treatment options available for thumb reconstruction. This algorithm was derived from our experience with 52 patients with congenital thumb hypoplasia or aplasia (n = 10) or traumatic amputations (n = 42). The available options for reconstructive treatment include replantation and revascularization, pollicization, microvascular transfer, lengthening, and web space deepening/lengthening. Using this algorithm, a rational decision can be made on the basis of the length of the remaining digit and the associated injuries. Often, patients with as much as 1 cm of proximal phalanx remaining may have good function and sensibility without reconstruction.

Extraperiosteal toe phalanx transfer for congenital aphalangia: refinement of technique.

Toe phalanges with attached periosteum can be transferred to hands with congenital aphalangia, constructing rudimentary digits with growth potential. Using a volar technique, rather than the traditional dorsal method, allows stabilization of the constructed metacarpophalangeal joint and maximizes flexor function.

Arthroscopic categorization of intercarpal ligamentous injuries of the wrist.

Recent advances in our knowledge of wrist ligamentous anatomy, as well as improvements in arthroscopic techniques, permit the diagnosis and treatment of a wide variety of wrist injuries. The authors review current concepts in wrist ligamentous anatomy, patterns of instability, and the role of the arthroscope in the evaluation and treatment of such instability. Specifically, wrist portal anatomy and techniques of arthroscopic treatment of patients with partial and complete intercarpal ligament injuries are described. Chronic complete injuries are a contraindication of arthroscopic treatment. The authors conclude that wrist arthroscopy provides a valuable method of diagnosing and treating partial and complete intercarpal ligamentous injuries.

The role of hip arthroscopy in the evaluation of avascular necrosis.

This prospective study evaluated the correlation between plain radiographs, magnetic resonance imaging (MRI), and diagnostic arthroscopy in the staging of avascular necrosis of the femoral head. Fifty-two hips in 46 patients were prospectively staged using radiographic and MRI staging systems. Patients subsequently underwent hip arthroscopy to visualize the articular surface prior to considering salvage of the femoral head and debride delaminated osteochondral fragments. Weighted Kappa analysis revealed only moderate correlation between MRI and plain radiographs (K=.11), MRI and arthroscopy (K=.21), and plain radiographs and arthroscopy (K=.19). Six (46%) of 13 patients with a radiographically apparent subchondral fracture demonstrated collapse of the articular surface at arthroscopy. Four (24%) of 17 hips with >2 mm of collapse of the femoral head on plain radiographs demonstrated fragmentation of the osteochondral surface of the femoral head at arthroscopy. In 5 patients with flattening of the femoral head, 3 patients had delamination of both the femoral and acetabular surfaces. In regard to labral pathology, 5 of 22 post-collapse hips also had large bucket handle tears of the labrum. Arthroscopy of the hip revealed osteochondral degeneration that was not detected by plain radiographs or MRI in 36% of post-collapse femoral heads.