Distal Ulna Implant Arthroplasty with Sigmoid Notch Resurfacing Utilizing Lateral Meniscal Allograft

Hypothesis: Despite the use of distal ulnar implant arthroplasty, the issues of implant instability and residual disability remain unsolved. This study reviews the outcomes of patients treated with a novel technique utilizing a lateral meniscal allograft for resurfacing the sigmoid notch to address the aforementioned concerns.

Methods: Following institutional review board (IRB) approval, a retrospective study was performed for patients who underwent distal ulnar arthroplasty with concomitant resurfacing of the sigmoid notch with a lateral meniscal allograft. The allograft was contoured and fixed to the sigmoid notch such that it recreated the palmar and dorsal radioulnar ligaments. At latest follow up, patients' range of motion, grip strength, postoperative complications, and radiographic evaluation were recorded.

Results: This series included five patients (three male, two female) with an average age at surgery of 63 years (range 53–71 years; Table 1). Average follow-up was 16 months (range 8–28 months). Postoperatively, there was an increase in the flexion-extension arc and pronation-supination by 32° and 31°, respectively. Average increase in grip strength was 39% of the unaffected extremity. Postoperative radiographs demonstrated satisfactory implant position without any signs of wear of the sigmoid notch. All but one patient experienced either complete resolution or marked decrease of their preoperative pain (Table 2). None of the patients developed subsequent implant instability, and none underwent any revision procedures.

Summary Points: Distal ulna implant arthroplasty with lateral meniscal allograft resulted in excellent patient outcomes without any signs of implant instability. Larger studies with a control group are warranted to further characterize the outcomes associated with the procedure.

Table 1 Preoperative patient characteristics

Patient No.	Age at Surgery (years)	Sex (M/F)	Dominant Hand (Y/N)	Prior Surgeries	Etiology	Operative Indication	Clinical Follow-up (Months)
Abbreviations: DRUJ, distal radioulnar joint; OA, osteoarthritis; ORIF, open reduction internal fixation; USO, ulnar shortening osteotomy.
1	53	M	Y	USO	OA	Symptomatic DRUJ arthritis, DRUJ instability, hardware irritation	15
2	59	F	N	USO	OA	Symptomatic DRUJ arthritis, DRUJ instability	28
3	75	M	N	Arthroscopy, TFCC repair	Posttraumatic Arthritis	Symptomatic DRUJ arthritis	20
4	55	F	N	Distal Radial ORIF	Posttraumatic Arthritis	Distal radius malunion	11
5	71	M	N	−	Posttraumatic Arthritis	Symptomatic DRUJ arthritis	8
Mean	62.6						16.4

Table 2 Pre- and postoperative ROM and grip strength at latest follow-up

Pt. No.	Preoperative					Postoperative					Change
	Pain	Wrist flex/ext (deg)	Forearm rotation (deg)	Grip strength (kg)	Grip strength (% opp)	Pain	Wrist flex/ext (deg)	Forearm rotation (deg)	Grip strength (kg)	Grip strength (% opp)	Wrist flex/ext (deg)	Forearm rotation change (deg)	Grip strength change (kg)	Grip strength change (% opp)
1	Moderate	131		16	37	No pain	140	160	24	86	9		8	49
2	Severe	95	105	30	65	Minimal	100	160	34	100	5	55	4	35
3	Moderate	95	155	18	72	No pain	130	155	30	100	35	0	12	28
4	Mild	45	145	8	25	Mild	140	170	20	57	95	25	12	32
5	Moderate	80	120	4	20	No pain	95	165	10	71	15	45	6	51
Mean		89.2	131.3	15.2	43.8		121	162	23.6	82.8	31.8	30.7	8.4	39