Faculty Bibliography

The management of complex cartilage and meniscal pathology in young, athletic patients is extremely challenging. Joint preservation surgery is most difficult in patients with concomitant knee pathologies, including cartilage defects, meniscal deficiency, malalignment, and/or ligamentous insufficiency. Clinical decision making for these patients is further complicated by articular cartilage lesions, which often are incidental findings; therefore, treatment decisions must be based on the confirmed contribution of articular cartilage lesions to symptomatology. Surgical management of any of the aforementioned knee pathologies that is performed in isolation typically results in acceptable patient outcomes; however, concomitant procedures for the management of concomitant knee pathologies often are essential to the success of any single procedure. The use of biologic therapy as an alternative to or to augment more conventional surgical management has increased in popularity in the past decade, and indications for biologic therapy continue to evolve. Orthopaedic surgeons should understand knee joint preservation techniques, including biologic and reconstructive approaches in young, high-demand patients.

Objective Focal chondral defects alter joint mechanics and cause pain and debilitation. Microfracture is a surgical technique used to treat such defects. This technique involves penetration of subchondral bone to release progenitor cells and growth factors from the marrow to promote cartilage regeneration. Often this results in fibrocartilage formation rather than structured hyaline cartilage. Some reports have suggested use of growth hormone (GH) with microfracture to augment cartilage regeneration. Our objective was to test whether intra-articular (IA) GH in conjunction with microfracture, improves cartilage repair in a rabbit chondral defect model. We hypothesized that GH would exhibit a dose-dependent improvement in regeneration. Design Sixteen New Zealand white rabbits received bilateral femoral chondral defects and standardized microfracture repair. One group of animals ( n = 8) received low-dose GH by IA injection in the left knee, and the other group ( n = 8) received high-dose GH in the same manner. All animals received IA injection of saline in the contralateral knee as control. Serum assays, macroscopic grading, and histological analyses were used to assess any improvements in cartilage repair. Results Peripheral serum GH was not elevated postoperatively ( P = 0.21). There was no improvement in macroscopic grading scores among either of the GH dosages ( P = 0.83). Scoring of safranin-O-stained sections showed no improvement in cartilage regeneration and some evidence of increased bone formation in the GH-treated knees. Conclusions Treatment with either low- or high-dose IA GH does not appear to enhance short-term repair in a rabbit chondral defect model.

PURPOSE: The purpose of the current study was to evaluate the short-term results of meniscal root repair surgery, assessing clinical and radiographic outcomes, utilizing MRI to assess root healing and extent of post-operative extrusion. METHODS: This was a single-center, retrospective study evaluating patients who had undergone a medial meniscus posterior root repair using a transtibial pullout technique with two locking cinch sutures. Demographic data were collected from patient charts. Clinical outcomes were assessed with pre- and post-operative IKDC and Lysholm scores. Pre-op scores were taken at the patients' initial clinical visit, mean 1.55 months prior to surgery (+/- 1.8 months, min 0.3, max 7.3). Radiographic outcomes were assessed with MRI evaluation of root healing, meniscal extrusion, and cartilage degeneration using ICRS criteria. Tunnel placement was evaluated and compared to the anatomic footprint. RESULTS: Eighteen patients (47.2 years +/- 11.9) were evaluated at mean follow-up of 24.9 months (+/- 7.2, min 18.4, max 35.6). The IKDC score significantly increased from 45.9 (+/- 12.6) pre-operatively to 76.8 (+/- 14.7) post-operatively (p < 0.001). Lysholm scores also increased from 50.9 (+/- 7.11) to 87.1 (+/- 9.8) (p < 0.001). Mean tunnel placement was 5.3 mm (+/- 3.5, range 0-11.8) away from the anatomic footprint. Mean extrusion increased from 4.74 mm (+/- 1.7) pre-operatively to 5.98 (+/- 2.8) post-operatively (p < 0.02). No patients with > 3 mm of extrusion on pre-operative MRI had < 3 mm of extrusion on post-operative MRI. Both medial femoral condyle and medial tibial plateau ICRS grades worsened significantly (p < 0.02 and p < 0.01, respectively). On MRI, one root appeared completely healed, 16 partially healed, and one not healed. CONCLUSION: Patients treated with the transtibial suture pull-out technique with two locking cinch sutures had improved clinical outcomes, but only partial healing in the majority of cases, increased extrusion, and progression of medial compartment cartilage defect grade on follow-up MRI. Patients should be counseled that although clinical outcomes in the short term may be optimistic, long-term outcomes regarding progression to degenerative arthritis may not be as predictable. CLINICAL LEVEL OF EVIDENCE: III.

Small animal models are critical for studies of sports-related knee injury and disease such as posttraumatic osteoarthritis (PTOA) following anterior cruciate ligament (ACL) rupture. In such models, ACL damage can be achieved by surgical transection or, using a more recent innovation, by noninvasive biomechanical means. Whether these approaches differentially alter normal mechanics is unknown. Furthermore, while surgical reconstruction of ruptured ACL can greatly improve joint stability, its effect on PTOA development is also unclear. Our primary purpose was to characterize rodent knee joint mechanics in two models of ACL rupture using a novel quantitative laxity mechanical test. Our secondary aim was to characterize a new reconstruction technique using autograft tail tendon, and to assess its effect on joint mechanics. Our hypothesis was that surgical ACL transection would have a greater effect on joint mechanics. A total of 24 rat knee specimens underwent surgical or biomechanical ACL rupture and were stabilized using a new reconstruction technique using autograft tail tendon. Joint mechanics were assessed three times; preinjury, postinjury, and again after reconstruction, using quantitative joint laxity testing. Primary test readouts were maximum anteroposterior (AP) laxity, loading curve slope, and energy absorption. Student's t-tests were performed to identify intragroup differences. All surgical transections were completed successfully; maximum load in the biomechanical model was 67 +/- 7.7 N, with a coefficient of variation of 11.43%. Surgical transection caused increased AP laxity, while biomechanical injury nonsignificantly increased this parameter. In both cases, these changes recovered to baseline by reconstruction. Loading curve slope was reduced in both models and was also returned to baseline by repair. Energy absorption followed the same pattern except it remained significantly different from baseline postreconstruction in the surgical group. This study supports our hypothesis knee joint mechanics is differentially affected by injury mechanism in a small animal model. We also report a novel reconstruction technique in this model, using autograft tail tendon.

Objectives: Continuous gradient-echo (GRE) acquisition or "dynamic magnetic resonance imaging", allows for high-speed examination of pathologies based on joint motion. We sought to assess the efficacy of a radial GRE sequence with in the characterization of patellofemoral maltracking. Methods: Patients with suspected patellofemoral maltracking and asymptomatic volunteers were scanned using GRE (Siemens LiveView WIP; Malvern, PA, USA) at 3T in the axial plane at the patella level through a range of flexion-extension (0-30degree). The mean time to perform the dynamic component ranged from 3-7 mins. Lateral maltracking (amount patella moved laterally through knee ranging) was measured. Patella lateralization was categorized as normal (<= 2mm), mild (2-5mm), moderate (5-10mm), or severe (>10mm). Tibial tuberosity: trochlear groove (TT: TG) distance, trochlea depth, Insall-Salvati ratio, and patellofemoral cartilage quality (according to the modified Outerbridge grading system) were also assessed. Results: Eighteen symptomatic (6 men; 12 women, age range 14-51 years) and 10 asymptomatic subjects (6 men; 4 women, age range 25-68 years) were included. Two symptomatic patients underwent bilateral examinations. Lateralization in the symptomatic group was normal (n=10), mild (n=2), moderate (n=5) and severe (n=3). There was no abnormal maltracking in the volunteer group. Lateral tracking significantly correlated with TT: TG distance (F=38.0; p<.0001), trochlea depth (F=5.8; p=.023), Insall-Salvati ratio (F=4.642; p=.04) and Outerbridge Patella score (F=6.6; p=.016). Lateral tracking did not correlate with Outerbridge Trochlear score. Conclusion: Lateral tracking measured on GRE was found to significantly correlate with current measures of patellar instability including, TT: TG, trochlea depth, and the Insall-Salvati ratio. GRE is a rapid and easily performed addition to the standard protocol for kinematic patellofemoral motion and can add dynamic information on patellofemoral tracking. This may be help determine if an isolated MPFL or an MPFL reconstruction and tibial tubercle osteotomy is needed to treat patella instability

The meniscus plays a vital role in knee biomechanics, and its physical absence or functional incompetence (e.g., irreparable root or radial tear) leads to unacceptably high rates of joint degeneration in affected populations. Meniscal allograft transplantation has been used successfully to treat patients with postmeniscectomy syndrome, and there is early laboratory and radiographic evidence hinting at a potential prophylactic role in preventing joint degeneration. We present a technique for lateral meniscal allograft transplantation using the CONMED Meniscal Allograft Transplantation system.

Over recent years, appreciation for the critical role of the meniscus in joint biomechanics has led to an emphasis on meniscal preservation. Meniscal allograft transplant (MAT) is a promising biological solution for the symptomatic young patient with a meniscus-deficient knee that has not developed advanced osteoarthritis. As surgical techniques are refined and outcomes continue to improve, it is vital to consider the utility of such procedures and offer a straightforward approach to MAT. This article and accompanying video provide a step-by-step tutorial on how to perform a MAT using the bridge and slot technique, its key pearls and pitfalls as well as the relevant advantages and disadvantages of MAT.