Treatment of post-meniscectomy knee symptoms with medial meniscus replacement results in greater pain reduction and functional improvement than non-surgical care.

PURPOSE: Partial meniscectomy is a common orthopedic procedure intended to improve knee pain and function in patients with irreparable meniscal tears. However, 6-25% of partial meniscectomy patients experience persistent knee pain after surgery. In this randomized controlled trial (RCT) involving subjects with knee pain following partial meniscectomy, it was hypothesized that treatment with a synthetic medial meniscus replacement (MMR) implant provides significantly greater improvements in knee pain and function compared to non-surgical care alone. METHODS: In this prospective, multicenter RCT, subjects with persistent knee pain following one or more previous partial meniscectomies were randomized to receive either MMR or non-surgical care. This analysis evaluated the 1-year outcomes of this 2-year clinical trial. Patient-reported knee pain, function, and quality of life were measured using nine separate patient-reported outcomes. The primary outcomes were the pain subscale of the Knee injury and Osteoarthritis Outcome Score (KOOS) and the average of all five KOOS subscales (KOOS Overall). Treatment cessation was defined as permanent device removal in the MMR group and any surgical procedure to the index knee in the non-surgical care group. RESULTS: Treated subjects had a median age of 52 years old (range 30-69 years) and one or more previous partial meniscectomies at a median of 34 months (range 5-430 months) before trial entry. Among 127 subjects treated with either MMR (n = 61) or non-surgical care (n = 66), 11 withdrew from the trial or were lost to follow-up (MMR, n = 0; non-surgical care, n = 11). The magnitude of improvement from baseline to 1 year was significantly greater in subjects who received MMR in both primary outcomes of KOOS Pain (P = 0.013) and KOOS Overall (P = 0.027). Treatment cessation was reported in 14.5% of non-surgical care subjects and only 4.9% of MMR subjects (n.s.). CONCLUSION: Treatment with the synthetic MMR implant resulted in significantly greater improvements in knee pain, function, and quality of life at 1 year of follow-up compared to treatment with non-surgical care alone. LEVEL OF EVIDENCE: I.

Preliminary Results From a US Clinical Trial of a Novel Synthetic Polymer Meniscal Implant.

BACKGROUND: At least 760,000 outpatient meniscectomies are performed in the United States each year, making this the most common musculoskeletal procedure. However, meniscal resection can alter the joint biomechanics and overload the articular cartilage, which may contribute to degenerative changes and the need for knee replacement. Avoiding or delaying knee replacement is particularly important in younger or more active patients. Synthetic meniscal implants have been developed in an attempt to restore the natural joint biomechanics, alleviate pain and disability, and potentially minimize degenerative changes in patients who require meniscectomy. PURPOSE: To evaluate the preliminary results from 2 ongoing trials that are evaluating the safety and effectiveness of a synthetic polymer meniscal implant (NUsurface; Active Implants, LLC). STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: This was a preliminary analysis of the first 100 patients enrolled across 2 studies for 12 months: a single-arm, intervention-only study and a randomized controlled trial comparing the investigational meniscal implant with nonsurgical therapy. There were 65 patients in the implant group (30 randomized) and 35 in the control group. Outcomes included Knee injury and Osteoarthritis Outcome Score (KOOS) and adverse events (AEs) collected at baseline and follow-up visits of 6 weeks, 6 months, and 12 months. RESULTS: No statistically significant differences were found in baseline characteristics between the implant and control groups. At 12 months, follow-up KOOS data were available for 87% of the 100 included patients. Significantly greater improvements from baseline were observed in the implant group compared with controls in all KOOS subcomponents, except for symptoms (119%-177% greater improvement at 12 months). AEs were reported at similar rates between the 2 groups, with 12 AEs among 11 patients in the implant group (16.9%) versus 5 AEs among 5 patients (14.3%) in the control group (P = .99). CONCLUSION: These preliminary results suggest significant improvements in pain and function scores with the implant over nonsurgical therapy and a similar adverse event rate.

High Rate of Early Revision After Custom-Made Unicondylar Knee Arthroplasty.

BACKGROUND: There has been a recent interest in custom-made partial knee arthroplasties to provide patient-specific instrumentation and better fit of the prosthesis. While unicondylar knee arthroplasties (UKAs) have demonstrated good outcomes and durable results in many studies, there is little evidence on outcomes of these custom-made implants. METHODS: We performed a retrospective review of all custom-made UKAs performed at our institution by one surgeon from 2008 to 2015. We analyzed preoperative demographics, clinical follow-up evaluations, and radiographs and performed an analysis of risk factors including age, gender, height, weight, body mass index, and tibial insert thickness. The incidence of revision surgery, radiographic failures indicating component loosening, and symptomatic clinically failed implants was calculated at an average of 54.0 months of follow-up. RESULTS: We analyzed 115 consecutive custom-made medial UKAs from a single surgeon at our institution and found 29 (25.2%) UKAs had failed at an average of 33.1 months after surgery. Reasons for failure included aseptic femoral loosening (10), aseptic tibial loosening (8), loosening of both components (4), infection (3), progression of osteoarthritis (2), pain (1), and dislodged polyethylene insert (1). We found a significant relationship between implant failure and body mass index; no other study variables were statistically significant. CONCLUSION: We found a relatively high rate of aseptic loosening and particularly femoral component loosening in the short- to intermediate-term follow-up period. While further study of larger numbers of custom-made UKA from multiple institutions may help verify these findings, we recommend careful consideration of the use of this implant.

Treatment of osteoarthritis of the middle-aged athlete.

Unicompartmental knee arthroplasty (UKA) has increasingly become an attractive alternative to total knee arthroplasty for early intervention. Clinical and biomechanical studies have shown that UKA offers advantages in early recovery, more natural function, and patient satisfaction. The literature has also shown that UKA exhibits a higher rate of revision than total knee arthroplasty, particularly in registry studies that include patients from outside of high-volume specialty centers. Patient-specific UKA offers the potential to close the gap between the known advantages of a partial knee solution and the documented risk of early revision. On the basis of the patient's own imaging data, patient-specific UKA allows for an anatomically matched implant design that provides personalized fit, full coverage of the tibial cortical rim, and preserves the femoral articulating geometry. These design advantages are paired with a patient-specific instrument system that provides reliable component placement and simplified balancing.

The safe zone for femoral cross-pin fixation: an anatomical study.

Femoral cross-pin fixation in anterior cruciate ligament (ACL) reconstruction has a potential for neurovascular injury, thus a "safe zone" must be defined for safe pin passage with this technique. In this anatomic study, femoral-sided, arthroscopic-assisted ACL reconstruction using the TransFix system (Arthrex, Naples, Fla) was performed on five fresh extended thigh and lower leg cadavers. Using a goniometer, five cross-pin guidewires were sequentially drilled at 0 degrees, -20 degrees, -40 degrees, +20 degrees, and +40 degrees, using the parallel to floor line as 0 degrees. Negative was defined as starting the pin more posteriorly, and positive was defined as starting the pin more anteriorly. Distance from the pin to the peroneal nerve, saphenous nerve, and femoral artery was measured after pin placement, and measurements were averaged. The peroneal nerve was at minimal risk with average distance to the guide pin of 1.87, 2.13, 2.45, 2.74, and 3.05 cm at -40 degrees, -20 degrees, 0 degrees, +20 degrees, and +40 degrees, respectively. The saphenous nerve was an average distance of 2.19, 1.98, 1.41, 1.42, and 1.29 at -40 degrees, -20 degrees, 0 degrees, +20 degrees, and +40 degrees, respectively. The femoral artery was an average distance of 1.81, 1.51, 0.78, 0.46, and 0.08 cm at -40 degrees, -20 degrees, 0 degrees, +20 degrees, and +40 degrees, respectively. Based on this anatomical study, the absolute neurovascular safe zone during cross-pin guidewire placement is from +20 degrees (0 degrees parallel to floor line) and -40 degrees (lowering guide more posterior).

Meniscal allografts: biomechanics and techniques.

Arthroscopic partial meniscectomy is one of the most common orthopedic surgical procedures performed. Numerous clinical and biomechanical studies have shown the long-term consequences of the meniscus-deficient knee, which includes increased loading of the cartilage. This leads to chondromalacia, and ultimately pain and dysfunction. Few treatment options are available for the young patient with pain in the tibiofemoral compartment secondary to meniscus deficiency. Meniscal allograft transplantation is a viable treatment option in this group of patients as short-term results have shown pain relief and functional improvement. Biomechanical studies have shown that the allograft meniscal transplant functions most like a native, intact meniscus when specific surgical principles are followed. Surgical techniques for meniscal allograft transplantation have advanced along with instrumentation. An improvement in function and pain relief can be expected when strict criteria are followed in patient selection and surgical technique.

The Krackow stitch: a biomechanical evaluation of changing the number of loops versus the number of sutures.

PURPOSE: The purpose of this study was to biomechanically evaluate several configurations of the Krackow stitch and determine which configuration provided the best fixation with regard to load to failure and elongation. TYPE OF STUDY: Biomechanical study. METHODS: Thirty fresh-frozen porcine Achilles tendons were randomly assigned into 6 groups. For 3 of the groups, 1 suture was used (No. 5 Ethibond; Ethicon, Somerville, NJ) with 2, 4, or 6 Krackow locking loops. For the other 3 groups, 2 sutures (interlocking and at 90 degrees) with 2, 4, or 6 Krackow locking loops were used. Data were evaluated using analysis of variance. RESULTS: There were no statistical differences in peak load to failure and elongation among any of the 1-suture techniques regardless of the number of locking loops (2, 290 N; 4, 302 N; and 6, 298 N; standard deviation, 25.2, 9.0, and 28.6, respectively). Similarly, there were no statistical differences among any of the 2-suture techniques regardless of the number of locking loops (2, 534 N; 4, 492 N; and 6, 505 N; standard deviation, 42.0, 65.4, and 76.3, respectively). There was, however, a significant difference (P < .05) in peak load to failure between the 1-suture and the 2-suture groups. The mechanism of failure was suture rupture in all cases. CONCLUSIONS: Load to failure did increase with the addition of a second interlocking suture placed at 90 degrees to the first. CLINICAL RELEVANCE: Tendon fixation with gap formation or suture rupture is at risk of failure. This study identifies that increasing the number of sutures is more important than increasing the number of locking loops.