Risk factors for anteroposterior laxity increase over time in double-bundle anterior cruciate ligament reconstruction using hamstring autografts.

PURPOSE: An anteroposterior (AP) laxity can increase over time after anterior cruciate ligament reconstruction (ACLR) using hamstring tendons; however, the associated risk factors remain unclear. This study aimed to investigate the risk factors of this phenomenon. METHODS: Overall, 151 patients who underwent ACLR using hamstring autografts were recruited. AP laxity was evaluated using Knee Lax 3 arthrometer at 5 months, 1 and 2 years postsurgery. Patients were categorised into groups I (>1 mm increase) and C (<1 mm increase) based on whether they experienced an irreversible increase in AP laxity after 1 or 2 years compared with 5 months. Patient demographics and Knee injury and Osteoarthritis Outcome Score (KOOS) at 2 years postsurgery were compared between groups. RESULTS: Group I (n = 33, 21%) showed a side-to-side difference of 4.6 (3.0-7.2) mm in AP laxity preoperatively and 0.3 (-0.7 to 1.3), 1.1 (0.2-1.9) and 2.4 (1.7-3.2) mm at 5 months, 1 and 2 years postoperatively, while group C (n = 119, 79%) showed 4.3 (2.8-5.7) mm preoperatively and 1.3 (0-1.9), 0.9 (0.1-1.8) and 0.6 (-0.3 to 1.5) mm, respectively. No significant differences were observed in the overall KOOS at 2 years (n.s.). However, group I was older (36 [22-46] vs. 28 [19-39] years; p = 0.044), had longer surgical waiting periods (122 [69-341] vs. 81 [52-136] days; p = 0.041) and lower preoperative Tegner activity scale scores (6 [5-7] vs. 7 [6,7]; p = 0.002). CONCLUSION: While 33 patients (21%) experienced AP laxity increase over time, they had comparable clinical outcomes with group C. LEVEL OF EVIDENCE: Level III.

Circumferential Cross-Stitch Suture for Longitudinal Lateral Meniscal Tear Around the Popliteal Tendon Hiatus Region.

Lateral meniscal repair of the popliteal hiatus is technically demanding. The inside-out technique requires an additional incision and carries the risk of posterolateral soft tissue damage to the knee joint. In addition, the presence of the popliteal tendon limits the route of the suture thread. Within the current trend of the all-inside suture technique, meniscal suture-based all-inside repair demonstrates biomechanical advantages over anchor-based all-inside repair. We introduce a meniscal suture-based all-inside meniscal repair technique for longitudinal lateral meniscal tears.

Fibular morphology is not associated with incidence of peroneal tendon dislocation.

PURPOSE: The association of peroneal tendon dislocation with peroneal bone morphology and postoperative redislocation rates remains unknown. This study compared the fibula morphology in patients with peroneal tendon dislocation with that in a control population. METHODS: The study enrolled 48 patients who underwent surgery for peroneal tendon dislocation at our institution during between 2018 and 2023. Thirty-five patients with preoperative magnetic resonance imaging of the ankle were defined as Group D and 35 with magnetic resonance imaging of the ankle for other reasons and with similar background data were selected as the control group (Group C). The posterior tilting angle of the fibula, posterolateral angle and posterolateral edge angle were evaluated at the plafond level. The posterior tilting angle, posterolateral angle and retromalleolar bone shape according to the Rosenberg classification (flat, convex, concave) were evaluated at the midpoint between the plafond and the tip. RESULTS: At the plafond level, the posterior tilting, posterolateral and posterolateral edge angles were 57.7 ± 11.1°, 123.8 ± 12.3° and 90.8 ± 13.7°, respectively, in Group D and 64.1 ± 15.4°, 121.1 ± 12.3° and 88.7 ± 12.2°, respectively, in Group C, with no significant differences. No significant between-group differences existed in the posterior tilting and posterolateral angles at the midpoint level. Moreover, no significant differences existed in distribution of the bone geometry according to the Rosenberg classification. CONCLUSION: There were no differences in morphology between patients with peroneal tendon dislocation and controls. This study provides useful information on the indications for primary surgery and whether bony approach is useful for peroneal tendon dislocation. LEVEL OF EVIDENCE: Level IV.

Quadriceps strength is an early indicator of return to competitive sports 1 year after anterior cruciate ligament reconstruction in adult amateur athletes.

BACKGROUND: Return to sports is one of the important reasons why athletes with an anterior cruciate ligament (ACL) injury undergo surgery. There are few reports on return to sports among adult amateur athletes (individuals older than the college age who participate in competitive sports). This study aimed to investigate the return of adult amateur athletes to competitive sports 1 year after ACL reconstruction and to identify the indicators for return to competitive sports. METHODS: Between January 2015 and December 2017, adult amateur athletes who underwent primary ACL reconstruction were retrospectively investigated. The rate of return to competitive sports 1 year after surgery was evaluated. The patients were categorized into two groups: return to sports group (R group) and non-return to sports group (N group). Pre- and postoperative range of motion, pivot-shift test, anteroposterior laxity, quadriceps strength, Lysholm score, and the International Knee Documentation Committee score were compared between the groups. RESULTS: This study included 78 patients (48 men, 30 women; age range, 22-53 years). Five months after ACL reconstruction, quadriceps strength was significantly lower in the N group than in the R group, denoting muscle weakness in the N group at that time. No significant differences were found in the other items between the groups preoperatively and 1 year after surgery. CONCLUSION: In this study, the rate of return to competitive sports of adult amateur athletes 1 year after ACL reconstruction was 76.9%. Quadriceps strength may be an early indicator of return to competitive sports 1 year after reconstruction.

Predictive factors for the bone union disorder of intramedullary screw fixation in proximal fifth metatarsal bone fractures.

INTRODUCTION: Although intramedullary screw fixation likely leads to successful union of Jones fractures compared to that of nonoperative treatments, bony union disorder after surgical treatment remains to be elucidated. METHODS: Intramedullary screw fixation was performed for the surgical treatment of proximal fifth metatarsal stress fractures in this series. Between January 2008 and December 2019, the feet of 222 patients were investigated regarding the effective factors for postoperative bony union between the normal union group and the bony union disorder group according to the patients' physical status, radiological assessment, and screw size. The mean postoperative follow-up period was 11.1 months. Bone union disorder was defined as delayed union, nonunion, or a re-fracture recognized through a radiographic image. RESULTS: The prevalence rate of union disorders occurred in 14% (31/222) of the patients. The risk of bone union disorder significantly increased when using a small-diameter screw (odds ratio 4.81, 95% confidence interval [CI] 1.62-14.2, p = 0.004) and non-bone graft procedures (odds ratio 3.13, 95% CI 1.22-8.02, p = 0.02). Screw length, preoperative Torg's classification, or patients' physical status did not affect postoperative bony union. CONCLUSIONS: Approximately 14.0% of the patients in our study had postoperative bone union disorder. Small-diameter screws and non-bone graft procedures increased the risk of bone union disorder in the intramedullary screw fixation technique of fifth metatarsal bone stress fractures. LEVEL OF EVIDENCE: Level 4, case series.

A Modified Anatomic Transtibial Double-Bundle Anterior Cruciate Ligament Reconstruction Provides Reliable Bone Tunnel Positioning.

Purpose: To evaluate the femoral and tibial tunnel positions via a modified anatomic transtibial double-bundle anterior cruciate ligament (ACL) reconstruction. Methods: Patients who underwent double-bundle ACL reconstruction using the transtibial tunnel creation technique were identified. Double-bundle ACL reconstruction was performed for 94 knees using the transtibial tunnel creation technique. Tunnel aperture configurations and center positions of the anteromedial (AM) and posterolateral (PL) tunnels via postoperative 3-dimensional computed tomography were evaluated. Results: There were 94 knees included. Regarding the intra-articular tunnel aperture configurations, the AM and PL tunnels overlapped at the femoral and tibial aperture in 66.0% and 94.7% cases, respectively. The mean femoral bone tunnel center was located at 23.0 ± 3.9% in the posterior-to-anterior ratio and 28.7 ± 6.0% in the proximal-to-distal ratio for the AM tunnels and at 32.8 ± 4.7% and 51.2 ± 5.2% for the PL tunnels, respectively. In the tibial tunnels, the mean AM tunnel center was located at 31.4 ± 3.6% in the anterior-to-posterior ratio and 44.3 ± 1.8% in the medial-to-lateral ratio and at 47.5 ± 3.8% and 44.3 ± 1.9% in the PL tunnel center, respectively. The femoral tunnels of outliers, both those created in nonanatomic positions as well as the posterior wall blowouts, were revealed in 7.4% cases. The nonanatomical bone tunnel group had significant heavier weight patients, lower tibial posterior slope, and were anterior in the AM and PL tunnel position. Posterior wall blowouts were related to posterior and proximal PL bone tunnel positions. Conclusions: Modified transtibial double-bundle ACL reconstruction is a reliable tunnel creation technique with anatomic placement in 92.6% of the cases. The modification required that partially superimposing configuration of the 2 tibial tunnel apertures. The nonanatomic tunnels were related to patients of heavier weight and lower tibial posterior sloped knees, whereas the posterior wall blowouts were related to the posterior and proximal PL bone tunnel positions. Level of Evidence: Level IV, therapeutic case series.

Less Invasive Surgery With Autologous Bone Grafting for Proximal Fifth Metatarsal Diaphyseal Stress Fractures.

Surgery with autologous bone grafting for proximal fifth metatarsal diaphyseal stress fracture has a potential to decrease nonunion, but it is not performed widely as the primary surgery because of donor-site morbidity. We have devised and performed a less invasive surgical procedure with autologous bone grafting and aimed to investigate the clinical and radiologic outcomes of this procedure. The data for 73 patients who underwent primary intramedullary screw fixation with autologous bone grafting from the fifth metatarsal base for proximal fifth metatarsal diaphyseal stress fractures were investigated retrospectively. The clinical and radiologic outcomes were evaluated. The mean time to bone union, starting running, and return to play was 11.8, 6.3, and 13.4 weeks, respectively. Bone union was achieved in 76 of the 78 cases. Intramedullary screw fixation with autologous bone grafting from the fifth metatarsal base showed good outcomes. It may be a useful surgical option for patients with proximal fifth metatarsal diaphyseal stress fractures.

Comparison Study of Mini-Incision Versus Original Open Technique of the Half-Mini-Bunnell Achilles Tendon Repair.

Mini-incision surgical procedures in our institution have been developed by decreasing the total skin incision length from the original mini half-Bunnell tendon repair technique. We hypothesized that the mini-incision, or minimum invasive Achilles tendon repair technique, would promote the tendon healing process leading to better outcomes and a reduced complication rate compared to the conventional open repair. The study sought to determine the more optimal method by comparing 44 mini-incision sutures to the 99 sutures in the original open Achilles tendon repairs. The mean skin incision length of the mini-incision surgery was 2.9 (range 2.5-3.0) cm and the original repair was 4.2 (range 3.5-7.0) cm. The mean surgery time was 60.0 minutes in the mini-incision repair and 68.1 minutes in the original one (p = .0003). The mean achievement time of bilateral heel-rise, starting jogging, single-legged heel-rise movement and the time to return-to-play was not significantly different between the 2 groups. Achilles Tendon Rupture Score was not significantly different from 3 to 9 months after surgery. Re-injury rate was 1/44 (2.3%) in mini-incision and 4/99 (4.0%) in conventional open repair (p = .36). No patients in either group developed any postoperative infections nor deep vein thrombosis complications. Although the mini-incision half-mini-Bunnell suture was showed equivalent clinical results to the original open repair, the technique is recommended in terms of curtailment of the surgery time without increase of complication ratio.

Muscle strength after the anterior cruciate ligament reconstruction via contralateral bone-tendon-bone autograft.

PURPOSE: The anterior cruciate ligament (ACL) reconstruction via a contralateral bone-tendon-bone (C-BTB) autograft was introduced to encourage early return to sports. The purpose of this study is to evaluate whether primary contralateral BTB ACL reconstruction can be adapted for early return-to-sports modification by investigating the chronological changes of muscle strength after surgery. METHODS: Fifteen patients who had underwent C-BTB ACL reconstruction were compared with a matched group of 15 patients of ipsilateral BTB (I-BTB) ACL reconstruction. The clinical outcomes of the time of return-to-sports, Tegner activity scale and the rate of second ACL injuries, the tibial anterior translation measurement, and knee extension and flexion muscle strength were assessed. RESULTS: Within 12 months after surgery, 14 of 15 patients from both groups returned to preinjury sports. The median time to return to sports after surgery was 6.5 months in the C-BTB group and 8.0 months in the I-BTB group (p = 0.021). No significant difference was noted with regard to the Tegner activity scale, reinjury rate or mean instrumental anterior tibial translation. The quadriceps muscle strength in the ACL-reconstructed knee compared with the opposite knee in both groups at 5 months after surgery was 120.6% in the C-BTB group and 70.0% in the I-BTB group (p < 0.001). However, the quadriceps muscle strength of the non-reconstructed limb, which instructed the graft harvested knee in the C-BTB and the intact knee in the I-BTB group, compared with that of the preoperative uninjured limb, was 74.5% in the C-BTB group and 118.7% in the I-BTB group (p = 0.0021) 5 months after surgery. Moreover, the quadriceps muscle strength of the reconstructed knee compared with the preoperative normal limb was 88.8% and 81.5% in the C-BTB and I-BTB groups, respectively (p = 0.38). CONCLUSIONS: ACL reconstruction via the C-BTB autograft indicated better quadriceps muscle strength from early stage after surgery compared with I-BTB ACL reconstruction. However, the ostensible rapid symmetrical muscle strength recovery was attributed to strength deficits compared to the preoperative condition at the donor site limb and ACL-reconstructed limb. LEVEL OF EVIDENCE: Level: Level: 4.

Can low-intensity pulsed ultrasound (LIPUS) accelerate bone healing after intramedullary screw fixation for proximal fifth metatarsal stress fractures? A retrospective study.

BACKGROUND: Intramedullary screw fixation is considered the standard treatment for proximal fifth metatarsal stress fractures. Low-intensity pulsed ultrasound (LIPUS) is a well-known bone-healing enhancement device. However, to the best of our knowledge, no clinical study has focused on the effect of LIPUS for postoperative bone union in proximal fifth metatarsal stress fractures. This study aimed to investigate the effect of LIPUS treatment after intramedullary screw fixation for proximal fifth metatarsal stress fractures. METHODS: Between January 2015 and March 2020, patients who underwent intramedullary screw fixation for proximal fifth metatarsal stress fractures were investigated retrospectively. All patients underwent intramedullary screw fixation using a headless compression screw with autologous bone grafts from the base of the fifth metatarsal. The time to restart running and return to sports, as well as that for radiographic bone union, were compared between groups with or without LIPUS treatment. LIPUS treatment was initiated within 3 weeks of surgery in all cases. RESULTS: Of the 101 ft analyzed, 57 ft were assigned to the LIPUS treatment group, and 44 ft were assigned to the non-LIPUS treatment group. The mean time to restart running and return to sports was 6.8 and 13.7 weeks in the LIPUS treatment group and was 6.2 and 13.2 weeks in the non-LIPUS treatment group, respectively. There were no significant differences in these parameters between groups. In addition, the mean time to radiographic bone union was not significantly different between the LIPUS treatment group (11.9 weeks) and the non-LIPUS treatment group (12.0 weeks). The rate of postoperative nonunion in the LIPUS treatment group was 0% (0/57), while that in the non-LIPUS treatment group was 4.5% (2/44). However, this difference was not statistically significant. CONCLUSIONS: There were no statistically significant differences regarding the time to start running, return to sports, and radiographic bone union in patients with or without LIPUS treatment after intramedullary screw fixation for proximal fifth metatarsal stress fractures. Therefore, we cannot recommend the routine use of LIPUS to shorten the time to bone union after intramedullary screw fixation for proximal fifth metatarsal stress fractures.

All-Inside Repair for Radial Tear at the Posterior Horn of the Lateral Meniscus: A Figure-8 Suture Technique.

Arthroscopic suture repair for a radial tear at the posterior horn of the lateral meniscus poses a technical procedure for surgeons. We describe an all-inside repair technique using all-inside meniscal repair devices without adding any accessory portals. This simple technique provides precise reduction and stabilization of the meniscus by pinching 2 all-inside vertical sutures consecutively across the tear site.

Morphology of Acute Achilles Tendon Rupture by Intraoperative Evaluation.

The purpose of this study was to clarify the morphology of acute Achilles tendon rupture (ATR) according to intraoperative evaluation. The morphology of 220 cases was evaluated retrospectively from intraoperative findings from June 2014 to December 2015. We noted 3 characteristics of rupture. First, we divided the ruptures into complete or partial type. Second, according to the level of rupture, we classified them into muscle-tendon junctional type, mid-substantial type, or calcaneal insertional avulsion type. Lastly, on the basis of the pattern of rupture, we divided them into transverse pattern, double-layer pattern, or Z-shaped pattern. All ruptured tendons were repaired with surgical procedures on the basis of the classification of rupture type or pattern. Of the total of 220 cases, 217 were complete ruptures (98.7%) and 3 partial ruptures (1.3%). Regarding the level of rupture, 5 cases were of the muscle-tendon junctional type (2.3%), 209 cases of the mid-substantial type (95%), and 6 cases of the calcaneal insertional avulsion type (2.7%). In terms of the pattern of rupture, there were 198 cases of the transverse pattern (90%), 10 cases of the double-layer pattern (4.5%), and 12 cases of the Z-shaped pattern (5.5%). There was significant gender difference only in the mid-substantial type. Although the morphology of a typical acute ATR was complete, of mid-substance type, and with transverse pattern, other types of ATR were recognized from the intraoperative investigation.

Anatomic Anterior Cruciate Ligament Reconstruction Using Rectangular Bone-Tendon- Bone Autograft Versus Double-Bundle Hamstring Tendon Autograft in Young Female Athletes.

PURPOSE: To assess the clinical outcomes comparing rectangular bone-tendon-bone (BTB) grafts and double-bundle hamstring tendon (HM) grafts used for anatomic anterior cruciate ligament (ACL) reconstruction in young female athletes. METHODS: From January 2014 to November 2017, young female athletes 20 years or younger who underwent primary ACL reconstructions by a single surgeon were identified. Patients with concomitant injuries, not being a regular sports participant, the existence of contralateral ACL reconstruction, and who did not have a minimum of 1-year follow-up were excluded. We searched the rate and time for return-to-play, clinical outcomes including chronological instrumental side-to-side tibial translation difference, and muscle strength. Second ACL injury rates between the 2 groups during follow-up period were evaluated. RESULTS: Twenty-seven BTB ACL reconstructions and 29 HM ACL reconstructions were performed. The mean follow-up periods were 35.2 months in the BTB group and 33.8 months in the HM group. The BTB group showed better knee stability in mean side-to-side translational difference via arthrometric testing of 0.6 mm in the BTB versus 1.7 mm in the HM group at 5 months (P = .01) and 1.1 mm and 2.0 mm at 12 months, respectively (P = .02). There was no significant side-by-side difference in quadriceps muscle strength ratio, but the hamstring muscle strength was significantly better in the BTB group. The graft reinjury rate in the BTB group and the HM group was 0% (0/27) and 10.3% (3/29) (P = .09), respectively. In contrast, contralateral ACL injuries occurred in 17.3% (4/27) of the BTB group and 3.5% (1/29) of the HM group (P = .12). CONCLUSIONS: For young female athletes aged 20 years or younger, the BTB group had better knee instrumental stability than the HM group without range of motion loss or knee extensor muscle strength deficit. Although there was no statistical significance in terms of second ACL injury, we observed fewer graft rerupture and an increasing rate of contralateral ACL injuries in the BTB group. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Deep MCL injury cases with arthroscopic findings of hypermobile medial meniscus: A report of six cases of arthroscopic meniscal suture repair.

MRI did not detect any abnormality in the medial meniscus besides high-intensity changes at the meniscofemoral portion of the deep medial collateral ligament. Although pure valgus stress test proved no medial joint widening at 0° and 30°, when an examiner applied knee valgus and tibial external rotation force, the patient experienced pain in the anteromedial knee joint that coincided with their refractory symptoms in individual specific activity. Arthroscopy investigation confirmed that the anterior to middle segment of the medial meniscus had excessively slid into the central direction by a probe-drawing manoeuvre; synchronous meniscal movement in the valgus and external rotation test was also observed. After arthroscopic meniscal suture to the lesion had suppressed the abnormal meniscal movement, the patients' refractory anteromedial symptoms disappeared immediately. From their common history of medial collateral injury and the high intensity at the deep medial collateral ligament, we assumed that chronic deep medial collateral ligament impairment sustained the hypermobility of the medial meniscus. Arthroscopic confirmation of hypermobility led to definitive treatment of a simple meniscal suture. Painful deep MCL injuries with hypermobile medial arthroscopic findings are not a rare phenomenon as previously assumed; however, surgeons often fail to recognize its latent clinical features.

Single-Stage Arthroscopic Anterior and Posterior Cruciate Ligament Repairs and Open Medial Collateral Ligament Repair for Acute Knee Dislocation.

Till date, there are no clear guidelines regarding the treatment of multiple ligament knee injuries. Ligament repair is advantageous as it preserves proprioception and does not involve grafting. Many studies have reported the use of open repair and reconstruction for multiple ligament knee injuries; however, reports on arthroscopic-combined single-stage anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) repairs are scarce. In this report, we describe a case of type III knee dislocation (ACL, PCL, and medial collateral ligament (MCL) injuries) in a 43-year-old man, caused by contact while playing futsal. On the sixth day after injury, arthroscopic ACL and PCL repairs were performed with open MCL repair. The proximal lesions in the three ligaments that were injured were sutured using no. 2 strong surgical sutures. The ACL was pulled out to the lateral condyle of the femur and fixed using a suspensory fixation device. The PCL was pulled out to the medial condyle of the femur, and the MCL was pulled towards the proximal end of the femur; both were fixed using suture anchors. Early mobilization was performed, and both, clinical and imaging outcomes, were good two years after surgery.

Hypermobile Medial Meniscus: A Case Report.

CASE: A 21-year-old college soccer player suffered from knee joint pain, but neither preoperative clinical examination nor magnetic resonance imaging could detect a precise diagnosis. Arthroscopy showed that medial meniscus hypermobility led to impingement of the femorotibial joint surface. After inside-to-outside meniscus suture, the abnormal hypermobility could no longer be observed. The player returned to sports without any previously experienced symptoms. CONCLUSIONS: We present a case report of the hypermobile medial meniscus without substantial tear treated by meniscal suture. A careful arthroscopy inspection was the key element of the diagnosis and subsequent successful surgical treatment.

A modified technique to reduce tibial keel cutting errors during an Oxford unicompartmental knee arthroplasty.

PURPOSE: Bone cutting errors can cause malalignment of unicompartmental knee arthroplasties (UKA). Although the extent of tibial malalignment due to horizontal cutting errors has been well reported, there is a lack of studies evaluating malalignment as a consequence of keel cutting errors, particularly in the Oxford UKA. The purpose of this study was to examine keel cutting errors during Oxford UKA placement using a navigation system and to clarify whether two different tibial keel cutting techniques would have different error rates. METHODS: The alignment of the tibial cut surface after a horizontal osteotomy and the surface of the tibial trial component was measured with a navigation system. Cutting error was defined as the angular difference between these measurements. The following two techniques were used: the standard "pushing" technique in 83 patients (group P) and a modified "dolphin" technique in 41 patients (group D). RESULTS: In all 123 patients studied, the mean absolute keel cutting error was 1.7° and 1.4° in the coronal and sagittal planes, respectively. In group P, there were 22 outlier patients (27 %) in the coronal plane and 13 (16 %) in the sagittal plane. Group D had three outlier patients (8 %) in the coronal plane and none (0 %) in the sagittal plane. Significant differences were observed in the outlier ratio of these techniques in both the sagittal (P = 0.014) and coronal (P = 0.008) planes. CONCLUSION: Our study demonstrated overall keel cutting errors of 1.7° in the coronal plane and 1.4° in the sagittal plane. The "dolphin" technique was found to significantly reduce keel cutting errors on the tibial side. This technique will be useful for accurate component positioning and therefore improve the longevity of Oxford UKAs. LEVEL OF EVIDENCE: Retrospective comparative study, Level III.

Gravity Equinus Position to Control the Tendon Length of Reversed Free Tendon Flap Reconstruction for Chronic Achilles Tendon Rupture.

Repair of chronic Achilles tendon rupture is a surgical challenge. We describe the use of a free turndown tendon flap augmentation raised from the proximal gastrocnemius aponeurosis. To control optimal tension or the reconstructed Achilles tendon length, we used an original method by referring to the gravity planter flexion ankle angle of the contralateral limb. Key aspects of the technique are described. A retrospective analysis of the short-term outcomes achieved in a case series (n = 56) is presented. The postoperative anthropometric findings are also presented to indicate the successful outcomes achieved with this technique.

Impingement of the Mobile Bearing on the Lateral Wall of the Tibial Tray in Unicompartmental Knee Arthroplasty.

BACKGROUND: Tilting of the mobile bearing relative to the tibial tray in the flexion position may result from the implantation of femoral components more laterally relative to tibial components during unicompartmental knee arthroplasty (UKA) using the Oxford Knee. The purpose of the present study was to compare femoral component positions after UKA using the phase 3 device and a novel device. We further evaluated the placement of the femoral components with the new device in the flexion position to determine the association with short-term prognosis. METHODS: The location of femoral and tibial components in the flexion position of 38 knees implanted using the phase 3 device and 49 knees using a novel device was assessed at 1 year postoperatively using radiography of the proximal tibia and distal femur in the flexion position. RESULTS: The femoral component was implanted more laterally using the new device than using the phase 3 device in the flexion position (P = .012), which caused the impingement of the mobile bearing against the lateral wall of the tibial tray. After UKA using the new device, 10% of patients exhibited the tilting phenomenon of the mobile bearing because of the lateral implantation of the femoral implant. CONCLUSION: To prevent implantation of the femoral component too laterally using the new device during UKA, knee surgeons should set the drill guide more medially such that the center of the drill is aligned with the middle of the medial femoral condyle.

Myositis ossificans after navigated knee surgery: A report of two cases and literature review.

Computer-assisted surgery is now a common procedure in the field of orthopedics. We present two patients who developed myositis ossificans, a rare complication after navigated knee surgery. Due to careful follow-up and conservative treatment, surgical excision was avoided in both patients with good clinical results. Development of myositis ossificans after navigated knee surgery should be considered in cases of thigh pain and restricted range of motion of the knee.